Regaining pain sensitivity

How many of you remember first hit or punch in the balls?
I was hit with the hand by a girl when I was 14. Karate like hit and I remember how pain build up, going to the floor, unable to stand up for long time.
Later becoming older with multiple BB experiences this initial sensitivity was lost.
Well, I was away for a while, having a vanilla girl friend I was in love with and BB was not in our menu.
It remains only a forgotten desire, somewhere in my imagination.
After 2 years we break-up because I need to move away and she could not follow me.
Anyhow I just re-started with light ball-busting, ball squeezing in an erotic massage salon, that have bdsm massage included.
After first slap in my balls I was speechless. My balls becomes extremely sensitive again. The pain is building up so beautiful with only one slap.
The girl was very intuitive letting me to enjoy the pain.
I wold like not to have numb balls again. I would like to preserve this regained sensitivity. The feeling is so great.