ADT diminished my libido so I didn't get spontaneously horny BUT I could still get aroused by a partner who went slow and with LOTS of foreplay. I was able to keep erections while on ADT with 100 mg of Viagra (a year later I'm down to 20 mg but that's part of sexual rehab after radiation) but about four months in lost the ability to reach orgasm.

Doctors tell a lot of men "you can't have sex while on ADT" so we just take it as fact when it isn't--it just takes a lot more effort that doesn't seem worth it initially but is definitely worth it once you get started.