Respond please

Okay so I talk to my friends about sex and stuff but never ask what I really want to ask.. which is before you start having sex and you suck the guys duck to get the pre cum off do they nut or what I'm really cursious and does more pre cum come after you suck the guys dick or its just at the begin please don't be mean I'm just really curious about this stuff because I'm getting older and will have to do this type of stuff