Breathing play a part to0.
1) Slowly insert your penis to yr gf CB.
2) In/out Gentlly slowly while breath in/out deeply.
3) Take a deep breath n Go fast then slow down to take a breath,
then go fast again and slow down. (Dun want to injury you gf
right?).
P/S: Also depends on what postion you f**king yr gf. Some postion
beri easily shoot out one.