the fact of the matter is your boyfriend has been jerking himself off and making himself cum since he was able to get hard. so he has years of experience to bring the table. my best advice would be to not just sit back with your mouth open waiting for his cum, you’ve got to watch and learn. does it look like he squeezes his dick hard? does he jerk himself fast or slow? is there a certain method to his madness? well remember his technique and try to duplicate it, but add in your mouth as well. surely if you can replicate his jerking off technique maybe with both of your hands as you look him in the eyes and tell him how bad you want his cum, he will lose control and and do exactly what you want.

good luck lady