OK, kids! Drop your knickers, bend over, and sing along!
♫*Who goes in the backsides of little kiddies?
Sponge-Bob Square-Pants!*♫ :eek:
Heh. Cute.
I suppose it’s funnier thinking it’s just a rectal thermometer, but it is, in fact, an oral, underarm, or rectal thermometer - as many are.
Still, sticking Sponge Bob up your arse is an option, which is pretty funny in itself.
I’m sorry. I just re-read my post above and it sounds almost snarky, or at the very least, balloon-deflating. I shouldn’t post while so tired.
Sticking Sponge Bob up one’s arse is very funny to me. 
You’re a trifle late to the party. 