it usually starts with just you and another guy in the steam room. I always wait for the other dude to make the first moves. If he's interested in jacking or more, he usually starts by moving his towel slightly off from around his waist. it still covers all or most of the crotch . he gradually starts rubbing himself around the chest, then moves down the torso; if he ends up with his hand near or under the crotch covered towel and lingers there I know there is a chance of something happening. I'll start doing the same thing; loosen the towel, have it slightly cover the crotch area, move my hand down and rub my thighs and have my hand end up at my covered dick. judging by his next move - if he goes back to this crotch and actually moves the towel to uncover a little more, I usually see a hardon forming or already hard. I remove my towel for a matching boner, then its jacking/blowing time. I'm lucky that I have found two married guys at my gym that like getting bjs in the sauna. they both are able to get hard and cum in under a minute. that's great for several reasons; you never know when someone might enter the sauna and you dont want to be mid blow when that happens. always keep the sauna fully steamed.
Have encountered similar scenes through the years as well! You never know who is UP for playing in the steam or sauna...