There are 2 BB pellet sized bumps on the vein of my penis just underneath the helmet. In addition to noticing this, I have noticed a distinctly less pleasurable experience masturbating and very short lasting erections when finally erect (such as whilst browsing pornographic material. In other cases I notice a tingling and urine sensation when masturbating. When retracted whilst flaccid, it feels as though the foreskin sticks to the the helmet and coils inside it as it rolls back up causing a dry and unpleasant feeling. This is alleviated by dowsing water over my helmet if only for a short time.