I am able to stretch the foreskin back past the glans during an erection, but the phimotic ring is tight and restrictive on the shaft on the penis, often caushing a "dent" on the underside of the penis. Furthermore, I cannot pull back the foreskin very far down the shaft due to a tight/short frenulum band, causing the foreskin to "bunch up" behind the glans during sex - this causes irritation for my partner. What can I do to stretch the phimotic ring and the frenulum band?