He was fucking like a machine

A couple of years ago I was living in one of those art-deco apartments in New York, I had upstairs neighbours who were awesome.
Two 20-something guys, nice and clean cut, but I slept below their bedroom, and I heard what went on.

One of them was like a machine, I used to lay awake in awe of this dude.
A constant rhythm, perfect sync, and I could tell he was hitting it deep for a good 30 minutes nonstop.

If I think about it I guess I should have been pissed off by these noisy neighbours, but at the time I was captured by the curiosity.
I must say it wasn’t a routine thing, it was happening randomly 2 or 3 times per week. But every time I was there, wondering whom of the two was this incredible fucking machine.

I was dying to know.

They didn’t look gay/bisexual or anything like that, I was just assuming that they were doing turns to get the flat “free”, I was doing the same when i was younger, and it was also explaining the 2-3 nights frequency, right?

After awhile I stopped doing these conjectures, I was just focused on the perfect rhythm and the power of those sessions.