it has more to do with swallowing a load of cum, than deepthroating. I'm not sure where we got fucked up but hey whatever I have smoked a little too much today.
I have had plenty of blowjobs (mostly from same person/s due to long term relationship) but have only ever cum twice from receiving one. First time was from a random guy, first and only gay experience, took him a while (40-45 mins or so) but got there eventually, couple of years after that my long term girlfriend managed to make me cum after working on it for about an hour and 15 mins. She has never managed it again since.