I like occasionally to bring the foreskin all the way up over the glans (if it goes that far) anstick my tongue into the foreskin. I'll let the foreskin kind of trap my tongue against the head, and wiggle my tongue around. In the past, this has yielded good results. I have also found that some men like the tension created by pulling the skin all the way down by the base, and holding it down tautly, firmly, but above all, gently. Meanwhile, go about your business sucking the way you like.
One more thing: is your tongue pierced? When i had a piercing, I used to slide the bottom of the barbell into the foreskin, the way i said I do with my tongue, and I'd flick the tip of my tongue over the tip of the foreskin, and over the glans, and I'd change the angle of my head and position of my tongue to slide the jewelry around inside. This was very well received.
