So since you lot have read so many Yaoi...

Can someone tell me if this is a thing:

In some Yaoi manga I've read, most commonly Japanese, there's this thing where the characters are saying some reference to or connected to a cat or dog, then that would be their position in bed when the sexy time comes on. Cat meaning a bottom and Dog as the top (I've read in a manga before that this is the distinction for top or bottom in japan. xD)

I just recently noticed this happening and now I'm curious if some how, it's present in a lot of yaoi...

Sorry, it's something so simple but it's just so funny that the authors would insert that clue before the sexy time. xD