So I create a sim, but for some reason the default clothing for her is a pair of sweatpants and a junky t-shirt. Regardless of outfit type. I was able to fix this through CAS, but there's one slight hiccup.

I went ahead and downloaded some adult mods, and whenever I command this sim to get naked, She never does. Instead, she changes into that awful sweatpants outfit. I have never had any other sim do this. It looks a bit silly when she and her husband are doing the dirty, he's all naked and she's fully clothed. For non-mod woohoo she changes into the outfit I assigned her. The sweats only show up when she's supposed to be naked. All the other sims undress when they're supposed to.

This is a relatively minor annoyance for me, but I'd still like some help.

Are the slacks and T-shirt EA clothes or CC?

[QUOTE=sweetdevil]Are the slacks and T-shirt EA clothes or CC?[/QUOTE

EA Basegame.

Have you tried removing the adult mods and seeing if that helps?
Does she have multiple career outfits? One time I had a Sim with a glitched career outfit and discovered the game had generated six Career outfits for her. Her Naked outfit may also be glitched and the game may have mistakenly assigned the T-shirt and sweatpants to it.