actually, there are prostate orgasms. they're not the same as an ejaculatory orgasm and don't usually result in ejaculation. it's more akin to how a woman orgasms, more "full body". they take a lot longer to reach and sometimes require a little body training to get into/get right.

the prostate also isn't extremely deep in the body and isn't usually hit by an erect dick, not directly anyway.

op, do a little physiological research in addition to watching some amateur gay porn and maybe reading some, too. avoid uke/seme stereotypes, and you should do ok.