Cock sucking

I have only sucked cock twice in my life. The first time was over 25 plus years ago and he started to stroke me with his cock in my mouth and I came in about 15 seconds. His cock was so big I just couldn’t control myself but the second time the guy was only 5 inches and the same thing happened. I guess sucking cock really turned me on then wonder if would happen a third time. I think if it does happen I end up with a cock in my mouth I hope I’m locked up so I don’t cum at all