Post Ejaculations

My male partner and I have discovered a sexual activity which we have not been able to find any information. One day after heavy sexual activity which he had ejaculated normally and his penis was back to relaxed state I was playing with him just for the fun of it. He was laiding back relaxed and I could tell he was enjoying the playing but he was still limp....then he tightened up and started squiring out "what looks like precum, it is clear, slick and sweet to taste " the more I played the more it cum out until he was just totally exhausted from it. We have done this often since and it brings him great pleasure. What is this? Has anyone else had this experience? We are in our late 50's. It appears the more often we have sex the less he squirts out after cumming normally. We just went 2 weeks without being together and he squirted out alot after he had already ejaculated a couple of times. Can anyone else give us any information or where to look?