What fantasy do you just keep coming back to and you can always count on to be fun? This could be RP, a doujin, or just simply in your imagination.

In Final Fantasy 14, there's this twink catboy character who gets partially turned into crystal. We see his whole arm crystal, and some sticking out of his collar on the side of his neck. We never see him shirtless and we don't get too many details

I like to imagine that the crystal covers a large part of his torso, that you can see his bones and guts through it, and that I can watch my cock moving inside him when I fuck him.

That's been instant boner material for the last few years.

I like to fantasize about marrying Kindred a lot.

Throatfucking a really hot emo (and/or) Asian girl til she cums from sucking dick. (Not really possible but...)

Or deep anal til she passes out tbh

Getting knotted

Bimbofication

I fantasize about magical situations a lot, particularly ones I've done RPs on. Things like turning a dad into a young woman, turning mom into an ice sculpture, fighting demons, mind controlling people. It's fun.

Being a god and creating a world where i can finally be happy, mostly a mishmash of various worlds from the media i've grown up with and the towns i have sentimental attachment to, making myself perfect, a world where everyone is my friend and nothing and noone can ever take them from me or make them into anything they aren't, having a family of my own and living life like a sitcom with 50's-70's wholesomeness but with 90's sensibilities.

Abandon futa robot craving for something else rather than being a top. Sees that a human has more passion, so she decides to either get owned or own them.

This is a really simple water-downed version I'm telling.

For me it’s something like I get home and I’m really sleepy and my playpartner who i have a big bro/lil bro dynamic with either takes me to bed to sleep together and then takes advantage of me being half asleep, touching me everywhere and fucks me, ooor
He invites me for cuddles while he plays games with friends or watches a movie and i get to sit in his lap, then he makes me blow him or he fucks me at the same time

I have a pretty vanilla fantasy where I'm just sitting and getting milked over and over and over again by a pair of fat tits until I'm a shell of a dude. Had this fantasy even before I got my first titfuck. And then once I did, I realized I was wrong, it was 10 times better than I could've imagined, so the fantasy of just getting repeatedly titfucked persists~

As a Bi guy, I got two depending on which gender I'm horny for.
If I'm horny over women, seeing a woman get cock hungry and sweaty while not being allowed to cum. Just seeing how horny she is by the time she gets permission to cum.
If I'm horny over men, I wanna have a shy and cute twink moan for me and choke me with either his cock or a leash.

fucking my highschool students after class (only the slutty ones that wear short skirts for me)

Either being in a circle jerk or frotting with someone.

Messing around with a roommate of the opposite sex. I dunno why, I just think it sounds so hot to fuck around with a roommate, and have casual sex whenever and wherever