As friends, sims can ask, or be asked, to "stay over for the night". And if they are love interest, it will change to "sleep over". However, none of the above means anything about "sleeping" at all.

Jenny was asked to sleep over by her love interest, Peter (who is also my current active sim). They can woohoo as much as they like, they even had a baby together (if you followed my older post). Except the only way to make Jenny sleep is to woohoo with her when her energy bar is low, and she would stay asleep in bed after woohoo. Or else ...

- Peter would give a tantrum if Jenny just goes to sleep in his bed (but he is ok with woohoo).

- Peter would give a tantrum if Jenny goes to sleep in .... another bed (just bought it to test).

Same goes with friends' sleep over. My active sim invited two of her female friends over for a "sleep over pillow party". I even made a separate guest bedroom just for guests to sleep. Same result:

- If I order guests to sleep in an unassigned bed (not belong to a household's sim), house owner gets a tantrum, tell off their guests.

- If I just let sims do their own things, guests will end up staying up all night, and probably pass out in the morning due to extreme fatigue.

Honestly, there is no "sleep" in "sleep over" for guests. The only way around is mod and cheat: make active guests, manually order guests to sleep, make active house owner, and cancel the complain when guests get to sleep.

Wow, that's really odd. I've never had any problems with sleepovers.. at least, I don't recall ever having any? I mean, the guests do stay up all night usually, but by the morning they are always sleeping in an empty bed. Actually, once, I had my sim ask his girlfriend to sleep over, and in the morning, when she left, she got angry at him and said "You didn't let me get any sleep! I'm leaving" or something to that effect. And sometimes, even when I don't ask them to sleep over, they do it anyway and take over the beds.. I guess you could say I do have problems with sleepovers, but it's the opposite problem of yours o_o.
I don't think any of my sims have been asked to sleep over at another lot, but when I command my sim to ask if he can stay over, his friends never have any problems with him sleeping in their beds.

Yeah, non active sims don't seem to ask your active sims to stay over if your active sim is house owner. Neither does your active sim to be asked to stay over if he is a guest. I think that option is mostly made for us to order manually.

"You didn't let me get any sleep!" Hmm I have yet to see that. I have got my guests to stay all night from party as I purposely wore them down. They would honestly stay until they have something to do (like work or school). And each and every time they will respond with "<sim name> has something to do, must be going soon" and they would leave for work even at up most fatigue state (can even pass out 3 times on the way down from my apartment).

My sim in Barnacle Bay asked his romantic interest to stay over and they did sleep all night in the same bed. But if I'm remembering correctly, I did have a problem with my Bridgeport sim - he would invite his girlfriend over, but she would never even get inside the apartment. She'd stand outside for a few minutes and then drive away and that happened repeatedly.

Wait.

Aren't sleepovers supposed to be about staying up?? Ha, I know that's counterproductive or whatever, but...

...when I was a kid, I had sleepovers all the time and sleep was the last thing on our minds.

Whenever I ask a Sim to sleepover, I have them do all kinds of things: watch movies, play games, the horizontal llama (if their like that), pig out, chat, have a silent disco dance party, get drunk, etc. Sometimes, they do pass out and go to sleep.

Oh of course, I had a lot of those in my teen age as well. It was not meant to "sleep". It was anything but that: pillow fight, gossips, game, chat, etc...

But technically, under any circumstances, the host should provide place for sim to sleep. What if it is not a bunch of teenager but maybe a friend who had a fight with her boyfriend, and she came over to cry about it. And the best thing you would do for her is calm her down, and give her a warm cup of tea and let her sleep a quiet night. So not all are parties and games.

Right, I agree with you. It's common courtesy. I offer you my home, you should be able to find somewhere to sleep.

I've had lots of situations where my teen or child Sims will ask a friend to sleep over and then that invited guest, upon accepting the offer, immediately makes their way to the master bedroom to go to sleep. WTF? That's okay but a guest cleaning up after themselves after having a meal is inappropriate behavior deserving of a finger wagging?

Actually I found out my scenario doesn't happen all the time. My guest just now bolted right for the bed (as I purposely made the guest to be very tired to begin with, by switching household). This same guest can use shower, eat, etc... without any recourse.

But after "ask to clean house" to the guest, one of his cleaning action triggered my sim's tantrum.

I've had this situation of sleepover guests not going to sleep quite often and I think that it has got something to do with the guest's age group. Because this has never happened so far with adults, only with children and teens. But I haven't tested this extensively yet to be sure.
The only quick test I ran was a few weeks ago with a couple and their child in their vacation home in Egypt. All adult friends that were invited to stay for the night did go to sleep autonomously after a while with no complaints whatsoever from their hosts. The child friends of the son, however, did not. They stayed up all night, ate from the fridge, watched TV and had an occasional nap on the sofa and in the morning left completely sleep deprived. I also tried once then to invite both an adult and a child simultaneously and the same happened. When the adult got tired it looked for an empty bed and went to sleep, the child stayed up. The adult left fully rested while the child dragged itself home and passed out as soon as it had reached its house.
I haven't really bothered therefore to use this feature anymore and just had my Sims ask whether they could stay for the night whenever they were at friends' houses, because there seems to be no problem with that.

Hmm, I haven't had any issues with sleepovers either, as long as there's an unassigned bed for them, or a double bed + they're good enough friends with the host(ess). They go to sleep when they're tired. But then, I'm not sure I've ever done it with kids.

Still looking forward to Generations and the sleeping bags though

Actually my first scenario between the 2 love birds, Peter and Jenny. They are a bit short of being girlfriend/boyfriend (somehow that option still doesn't pop up yet). They had an accidental pregnancy a while back. Jenny still comes over often (because Peter lives alone while Jenny isn't).

I didn't give any extra bed. They woohoo in the same bed. Jenny came over, took shower, slept, ate meals cooked by Peter, taken care by Peter (role playing gestures). And she did all these just fine during the pregnancy.

However, it starts to happen now that whenever Jenny comes over, she refuses to automatically sleep in the same bed (unless after woohoo). But I can't just make them woohoo about 10x a night just to get them both to sleep together. And my only way to make them sleep is to switch household to make Jenny sleep, and when the guy gets up and gets ready to give her an earful, I switch household back to cancel that autonomous command. But he still carries the "Rude guest" moodlet.

This sleepover problem already exist since TS2...

I thought EA will fix it in TS3, but apparently is not.

I hope EA take a note seriously this time and will fix it in Generations (with sleeping bag item), or with a patch.

@tomomi1922 maybe Jenny has more sense than to be his girlfriend as Peter doesn't sound very nice ;-) All those tantrums and mood swings he has will send her into the arms of another sim!

eta: the reward 'Inappropriate in a good way' is worth it's weight in gold for socialising in another sim's house, I think.

This happened to me. My teen has the heart potential interest" with her neighbour and after asking to sleep over he said yes but they refused to sleep in the same bed together.... heh. Also sometimes, the romantic option of asking to sleep over never came up at all. Sometimes it only came up after 10pm... actually quite a few times it never came up no matter how many interactions I used, forcing my teen sim to try stealing a bed until she gets kicked out.. or heading home after 1am in the morning.
I also use inappropriate but in a good way which helps alot... but the rude guest/forced to go home gets annoying..

And I always thought that asking guests to sleep over/stay in for the night is just to prevent them from leaving after 11 pm/12 am.

i want a mod to ask friends to sleep over.that will be real friendship