Whenever you’re out and about with your dad, and you see attractive women, point them out and make “innocent” comments about how attractive she is, and ask your dad’s opinion on them. Maybe drop a “MILF” (without saying “MILF”) in the conversation once in a while.

[you noticing a mom with her kid(s)]

You: Hey dad, she’s pretty hot, no?

Dad: [grumbles] yeah sure. I guess.

You: Not hard to believe she’s a mom.

[blank stare him for a few seconds before quickly changing the subject]

You could also sneeze once in a while, asking him if he has any tissues you could use. If he says no, you could respond, “surely you have tissues somewhere, no?” Blank stare him for a few seconds before changing the subject. Same thing with asking for any hand moisturizer.

But don’t come right out and say anything to him about it. You want him to sit uncomfortably with this nagging doubt that maybe you know, but maybe you don’t.

Edit: damn. Y’all ain’t got no sense of humor over here @lemm.ee. I’m a dad, and if my kid did this to me, I’d find it hilarious. Lighten up a little. Life is too short, and there are very few things to laugh about. This should not be one of them.