The "song and dance" in Japan is very different. Guys are generally shyer, but the open layout (bunk beds on one side of the room, mattresses on the floor on the other) works this way: A guy lies on a mattress and pretends to be asleep. Sometimes completely naked, sometimes with a bathrobe. You come closer and start touching him. He might take a peek at you. If he's not into you or not into what you're doing, he will turn away or brush your hand away. Otherwise, he will let you continue.
Might deserve a separate post but as a cumslut, I really enjoyed the blowjob bars. It is what it says on the tin. You enter, there's a small bar and a bartender. Pay the fee (roughly $10), take a glowstick bracelet. They're color coded: red (I wanna suck dick), blue (I want my dick sucked), multicolor (either/both). There may be either a door or a curtain beyond the bar, which leads to a maze of cubicles and some larger rooms. Complete nudity as well as fucking are expressly forbidden, but you can binge on dick and cum.