Dude, you can't possibly be serious? You're trolling right? My bf is also younger than me and the last thing I'd do is give him any bate to call me a cougar or dear god - "Mommy". Like... be grateful he stopped at "cougar" and respect his boundaries. He's not into your kink, don't force it on him. And if it matters to you that much ("the only thing that makes you happy" - seriously?) then find someone your own age or older, they are more likely to enjoy being called daddy. But also, just... work on your understanding of consent and stop trying to figure out how to force your bf to bend to your will, it's not ok, he's a person, not a sextoy.