I think the word you are searching for is "cocktease" :P
Nyahahaha thanks for the right word. I learn everday here. Hahaha
I did read the chapter again and think he was really doing it but stopped midway and switched to the friggin dildo.
I wondered about that too, but after Sangwoo pulled Bum's underwear down, there's a panel right after that shows he's looking away. Why is that? 1) I think the "...." was to show Sangwoo wasn't totally on board with doing it and 2) He's looking in the direction where the dildo was and so he formed his cruel idea.
During the act, Bum also thought "This feels familiar..."
Anyway, this is my own take on it. Unless this is addressed later, it's really the reader's choice to decide whether Sangwoo did it or not.
Righhttt. There was that time that bum said it was familiar. Gosh that was so cuel huhu hope he did it midway. Huh
So this is what they say cockblocker. Lol i seriously thought sangwoo was doing him. Goshh hahaha