pegging comes over time
i started just growing up with an older sister and two older female cousins, the four of us always playing meant dressing me and stuff.
i think on some stupid tv show like clarissa or something i saw a girl put a guy in a trashcan too, started getting naked in my sisters little wastebin when no one was around
get older and the crossdressing seeds sprout into stealing sisters panties to wear
wrestling with sister and getting headscissored or my cousin jokingly putting her butt in my face planted more seeds
up into and through college those turned into wrestling/fighting/power, facesitting, losing, etc shit which i started to see in youtube and other sites' videos searching like boy vs girl, brother vs sister (didnt help that any episode of any show with boys vs girls gimmick always had girls winning)
one girl online found out about my panty crossdressing and wanted to peg me but i was totally against it.
years later after having so much of it in porn i think it grew on me
now in japan i had a dom gf who didnt seem dom at first, but starting with my dick she moved down to my balls, and then finally started poking at my anus until she started to finger me all the time and making thrusts into my backend even when out and about.
finally we decided to have her strapon fuck me and ever since i cant have it any other way