I don't know if you're actually serious!? I'll assume so!
GOOD GOD NO! PLEASE! You know how many girls would LOVE a guy like you? What happens if you reduce the size of your ting and your girlfriend leaves you?
Think about this... in one year, 2 years, or 5 years what will i regret having done?
It's a matter of training per se... be gentle. Yes it's going to be torturous for you at times, but eventually your girlfriend will be used to your size.
#DontBeLeftWithABatteredSausage