Call him out jokingly

Jonathan waits for Brian to peek again, and all of a sudden says:

"Hey, Brian, my eyes are up here haha"

Brian shakes his head quickly and look to the surgeon:

"Oh... what do you mean dude?"

Jonathan now has opened the topic he wanted:

"Man, you were totally checking my bulge, cmon now. Do you like what you see?"

Brian blushes:

"Oh I am sorry dude, I must have not realized, I went blank for a sec"