musclemonkey speaks the truth. However, I wonder if there is a proportional size relationship between the size of our dicks and what our sphincters can accommodate. My ass is basically retired. Has been for quite a few years. But when I was a young man as long as my partner had about a 6" dick I usually didn't have any trouble getting fucked -- unless the guy didn't know what he was doing. However, that didn't mean I always enjoyed it. Guys with larger dicks were always a problem. For a long time I couldn't understand how me fucking someone who was really into having me plow him -- and I mean PLOW WIDE AND DEEP -- could possibly enjoy it and be sexually stimulated. But they do. It would have made me pass out from pain! Frequently I had to work up a sense of anger as well as be horny in order to perform for the size queens who sought me out. I'm not into anger, pain, blood, scat, SM, etc. I like to suck cock, kiss, make love all night just docking with my partner keeping us both on the edge with precum, etc.
But I have had several lovers in my life who were hung, knew what they were doing and with whom I was so erotically attracted to they probably could have fist fucked me and I would have enjoyed it. In addition to the mutual erotic attraction I'm certain there was something chemical about our attraction -- pheremones? Hell if I know. Wish I did. I only had one relationship where I could slip my partner's cock up my ass easier than drinking a glass of water. But in those pre-condom days we used lots of Vaseline -- REALLY BIG JARS of Vaseline. He was almost as big as me. But I swear that in the days when we fucked without condoms it was much easier to take on a guy with plenty of foreskin than someone who was cut. Although I like both (I prefer uncut, like me).
Isn't there at least one proctologist who is a member of LPSG who can answer these Kosmic Kuestions?