Fun air game with a used condom

Tights with a hole for the small penis are a cool thing. So on the bed I'm wearing a condom with sperm on my cock. I was on the road and jerked off in the car. I then left the cum in the rubber over the flaccid penis and went shopping. Now at home I want to see if you can inflate the condom to play with the glans in the sperm. But somehow I can't get the part tight enough - or the pump doesn't have enough pressure to inflate the rubber. Well - it was kind of a funny experiment and the sperm is frozen again