Only once have I cum more than once in a session, a young lady was giving me head, one of the best BJ's I have ever had, combination of very deep and shallow sucking, plenty of eye contact, I could feel myself about to blow, I told her she just smiled, I came deep in her mouth, she swallowed like a good girl should.
And she just kept going, head bobbing up and down, sucking hard, my knob was so sensitive and within a minute or two, BAM, another load down her throat.
It wasn't anything I did, I didn't prepare for it, it just happened and has never happened again. Man, she had some skills.