he should be fine, just don't do it again. you could have messed up the boy's junk.
a hairband is not safe to use as a cock ring. hair bands are too thin; a cock ring needs to be at least 1/4 inch wide. too thin, and you're pinching off blood supply, not reducing blood flow like you would with a cock ring. if you don't have a perv friendly shop in your area, hit up the local home depot (home improvement center) to pick up a few silicone gaskets.
the bruise isn't really a bruise, he probably ruptured a blood vessel. you can see on the picture the bruise is sitting right on top of a vein. i would guess he either popped a bleeder or he bent his cock and couldn't feel it due to loss of sensation. if he's not in pain; doesn't have any numbness or noticeable changes in the quality of his erections, then he should be fine.
it's all fine and good to experiment but you need a basic knowledge just for safeties sakes.
ml
cock ring 101
1. metal cock rings should only be put on a flaccid penis.
2. a semi is more fine for rubber, silicone or soft cock rings.
3. if there is any pain, if the skin feels cold, numbness or abnormal swelling remove the cock ring immediately. *best to start with silicone, velcro or leather with snaps*
4. beginners should give their cock a breather after about 20 mins.
5. a good rule is one pinkie width between the ring and the cock when the guy isn't erect.
