Previous to the act of masturbation, an Insurance Piss is the act of urinating immediately after the primary finish. This is to ensure that the individual can avoid cleaning up his Second Wind. (See Second Wind).
Paul was tired of cleaning up his Second Wind, so he began trying an Insurance Piss. This way he could pee and not worry about a secondary clean up.
Previous to the act of masturbation and the primary finish, it is when the penis exerts tiny amounts semen from the penis after a first clean-up has already been made. Usually resulting in minor to major inconvenience for the individual who participated in masturbating.
Paul just finished all over himself after masturbating and cleaned up. He sat down and a few minutes went by when he looked down his pants to find there was some left over semen coming from the tip of his penis. He then ran to the bathroom to go and clean up his second wind.