I want to make some unique tats that can cover the whole body, but I don't know where I can do that. Plus I am having trouble downloading some tats from here to the game. Can anyone be of service?

Thanks,
Bigmunk2

Well, you have a few options.

You can use Cmar's tattoo program and tutorial to make regular Ambitions tattoos, which would then need to be used with the XCAS core mod to allow them to be placed as full body tattoos. This is a logical method, can be used with CASt and works with the game's systems (like the tattoo chair), but it does mean that anyone wishing to use your tattoos will need XCAS.

You can use a skintight accessory, such as gloves or socks, to make an overlay which will be applied on top of the skin. This has the advantage of being CAStable, like the above, and does not require any other mods. However, it won't work with the tattoo chair, and the tattoos will vanish when the sim is naked.

You can make a skintone with your tattoo drawn onto the skin. This would not be CAStable, but would not need extra mods, and would not vanish when the sim is naked. You would, however, be limited to using just the skintone you use as a base for your tattooed sims, and you might have trouble making the tattoos work well with the skintone sliders, though of course you can edit them.

Just adding that NRAAS MasterController with the expanded tattoo addon will also support full body tattoos without XCAS or any core mod, and that once the tattoo is in place all that's needed to keep it there is the Tattoo Locations package from either XCAS or MC expanded tattoo.