Love everything about swallowing. Never sucked a human male but would under right circumstances. I also would need to swallow before I cum myself. All desire disappears for me once I finish, unfortunately.
Quick story because thinking about it gets me super horny, so why shouldn't you? Lol.
Years ago when I had my first zoo experiences, if I was home alone or I thought I could get away with it at night, I would jerk my buddy off because seeing him cum was an amazing turn on. At first I was curious and thinking "this is wrong" but then the guilt subsided because it seemed like he really enjoyed it and it is not like I was hurting anyone. Eventually, I started giving him BJs to the point where I got into a routine.
Every few days (usually in my bedroom, although there were a few times in the basement and garage), I would get him excited and then lay in the same position so he knew it was playtime. I would get him hard with my hand, then once he stopped humping all over the place I would lay under him with my head propped up by a few pillows, and then suck him off.
I would keep my hand behind his knot to make sure he got constant stimulation and basically just milked him. He would cum straight down or at an angle into my waiting mouth. I would drink him down for 10 - 15 minutes at a time. Depending on my mood, I would either drink him down quickly or let it build up in my mouth until I swallowed it in one big gulp, and then repeat. He was panting all the while with that big dumb smile on his face. I must have sucked him off 100+times. He must have been the happiest dog in the neighborhood.
He passed away and I never had an intact pup since. I rescue and most rescues will spay/neuter before they put the dogs up for adoption. No rescue I ever had really showed any interest. I really miss those days.