do you think blowjobs when having sex is something normal?
It's called foreplay and it's normal. Think of it as the pre-work you gotta do to make it MUCH more intense during the actual intercourse. Think to yourself, "I'm doing this now because it will pay off later." It's customary for the guy reciprocate the favor.
and to guys, does your girlfriend give you bj when you ask? or is she uncomfortable doing it.
The more aroused I am, the longer I can last. Foreplay works wonders in making the arousal happen and I expect my partner to already know this. If she has a pushy attitude, that's so high school and is actually a turn off. Doesn't help AT ALL in getting it up. I'll ask for it, but if she resists I don't push it. That kills some of the moment. I'll just give more upfront to compensate and get her warmed up. It's up to both of you how much you want to do to make it mutually enjoyable!