When it is a Teenage Mutant Ninja Turtle.This may be unusual (or not) but my sister picked up this TMNT snuggie in a super great Hot Topic sale last week. (totally linked that for you if you wanna buy it!)
It's incredibly over-sized and super warm! I don't personally wear snuggies, but they have been a wonderful blessing to my mom with her arm deal.
Also, this is probably the only piece of clothing my sister and I can share! (if you recall what she looks like.. she's a stick!)
It's sad to think in only 11 short days, I will no longer be a teenager. Teens (and old people) can get away with doing so much ridiculous stuff. I guess I have my old age to look forward to!