I'm average size (both limp and erect), with foreskin that fully covers (but does not extend past) the head. I thought I'd detail how I successfully wear my CB6000. First, the 6 vent holes have to be plugged up - there's either too much fleshy skin, which pokes through and turns red; or there are very small blood vessels, which poke through and turn red - definitely not good. I use first aid tape from the pharmacy; looks a bit like Scotch tape, but it's slightly stretchy and waterproof. Put it on the inside of the tube, which can be a challenge, covering the holes. Stays on nicely when you wash the tube with dishwashing liquid. Other people suggest filling the holes with epoxy or putty. Second, cover the entire inside of the shaft with lube, whichever of the following methods you use. Third, you need the smallest spacer you can comfortably bear; after all, your scrotum is the locking mechanism. But you want the SECOND-smallest ring you can handle; you want a little room at the bottom of the ring so that you don't crush the ureter (behind your balls, near the asshole). Take a couple of weeks to move to smaller and smaller parts, you'll get used to it. I'm very comfortable now. Fourth, what to do with your foreskin. Method #1: Use the stocking method, and wind up with foreskin covering the entire head. Bad points: the foreskin can poke out of the slot and get pinched (you can put tape over the slot, but that gets to be a hassle after a while). Cleaning after a day or two requires removal. And your foreskin (mine, at least) gets an imprint from the weld. Face it, the CB6000 was not built for the extra thickness that the foreskin provides - it's a snug fit. Good point: your penis feels like it's not there. At all. Gone. No sensation. Method #2: Start with foreskin covering head, then insert penis until tip is at the ridge (corona) of the plastic head. Then, while continuing to insert the penis, allow the shaft of the CB6000 to pull the foreskin back. With practice, you can end up with foreskin completely retracted; head completely inserted; and (this is important) no skin stretched. A lubed Q-tip through the slot can help place any unruly bits. There will be a pileup of skin between the ring and the body of the CB6000, and you'll need a Q-tip (or a dull pencil) to hold it out of the way of the spacer while inserting the pins. Good points: cleanliness over a period of days. No foreskin sticking out of the slot. Bad points: the extra skin under the spacer (and your scrotum skin) can feel pinched - I'm used to it, but your mileage may vary. Another good point: the sensations during the day are incredible !! I'm not a believer that foreskin (or not) affects sensation during sex, but when you're usually covered, being uncovered and continuously rubbed during the day gets your attention! (That last may not be a good point, if your goal is to stop excessive masturbation. But your next sexual experience will be wonderful!) Method #3: a mix of #1 and #2. Use either the stocking (and a lot of practice), or a large bunch of foreskin pushed past the tip before Method #2, but the goal is to end up with foreskin covering 2/3 of the head when you're done inserting. You'll still feel your penis, but it won't drive you nuts, and there's no excess skin, either through the slot or under the spacer. This requires a lot of skill, and I always need 3 or 4 tries before I get it right. In practice, I use #1 and #2 much more than this.