Hi, I was having sex with my girlfriend. She was on top and I felt a slight pop from my penis. Not quite the same as cracking a knuckle but a quiet crack/pop. She didn t even notice. There was no pain, no swelling, no loss of erection and besides me being paranoid no further symptoms. We were able to finish just fine. This has happened maybe twice in the past all during change in angle of insertion. No symptoms associated with those instances either. I m just worried. I have no trouble getting an erection or ejaculating. Is this serious?