Honestly, I'm really discouraged. All the guys in porn seem to be able to spurt gallons of cum. When my college girlfriend and I fuck, I only have maybe 2-3 big spurts aka white ropes followed by lots of dribbling. She thinks she is at fault but I think I just don't produce enough. She has started to count each spurt and we measure for volume now to see if I'm increasing or not. We chart it on an Excel spreadsheet and so far, no improvements. What can I do to better improve my cumshot and volume?