From the gay bottom side of the spectrum :-). For me, a Mans piss is another form of His seed.
my first experience was with a Fuck Buddy who bred me on a regular basis. Always the same scenario, He'd let me know when He wanted to fuck and breed me, and i'd be waiting naked, ass up on my bed, blindfolded and door open. He'd usually come in, mount and breed me while talking 'dirty' to me, but honestly, "dirty" was really a sort of simultaneously affectionately degrading/humiliating affirmation, which turned me on and made me feel sort of possessed by Him. Usually, after seeding me deep (He was long and got past the S curve), He'd spank and caress my ass some, or just leave.
One time, after He came, He stayed deep and relaxed His full weight on me and i felt His Cock twitch and started to feel a warm fullness inside, not unlike getting an enema, and i realized He was pissing inside of me. i had a surprised response, that He anticipated and He whispered in my ear telling me how could He felt asking me to please take it. He knew me well and knew how much i connected to His pleasure. i got turned on and relaxed and took it as He continued to whisper encouragement into my ear. It was hypnotic for me. After He filled me, He pulled out without spilling a drop, and since He was past my S curve, i was able to hold it in without difficulty. i'm blind folded, but He whispers in my ear before leaving thanking me for being His toilet and asking me if i liked being that... i felt myself blush as i answered "yes." i slept with His piss in me overnight, when i got up to pee, i could smell His piss in my pee and for me it was a form of true impregnation, He definitely had me.
There's a lot of mind fuck in piss for me. Since then i started to fantasize about drinking a Mans piss from His Cock, but was afraid of what it would taste like and whether i could take the quantity. i tried tasting some of my own pee and figured i'd be able to tolerate it. my biggest fear is disappointing a Man Who really wants that, i don't want to fail. i finally got brave enough to ask a FB if He wanted to and He said "okay." The first time, i held about 2 inches of His semi rigid Cock in my mouth. He started to piss and i was surprised that the amount didn't overwhelm me, but about half way through, the taste got to me, so i only swallowed about half. The second time, i got better, and did about 2/3. But part of what was missing was His desire... i connect to a Mans lust, not really into just mechanical and i couldn't tell if He was just going along with me.
The last time i tried it was with a Man who is really into it. We had a really long fuck/breeding session, and He was very into opening me and we were both really turned on, even after He came (i never come, for me, His orgasm in me becomes my orgasm, and it's very fulfilling for me). After, He got up to shower and asked if i wanted His piss? I said "yes," and went and knelt in my walk in shower. He put a couple of inches of His flaccid cock in my mouth and immediately started to piss a strong stream. That took me by surprise because my other experiences the Guys were slower to get started. i actually choked at first, not expecting it, but was determined to take all of Him, and recovered and kept swallowing . He was telling em what a good job i was doing, and that just made me happy and kept me going till He was done. After He patted my head and said: "you took that like a champ." i felt really happy and proud of myself, and embarrassed at the same time that i derived so much satisfaction pleasing Him that way... but i did.
i still do not like the taste of piss, and have to psyche myself past that, but when a Man is obviously pleased by it and enjoying it, that's all it takes to keep me going.