My sub has recently expressed a desire to start playing with CBT - we've done a few sessions over Skype, and he says they have been some of the best and most powerful orgasms he's had. So far, we've been keeping things low-tech: clothespins and rubber bands, but I know he's interested in more.

Is there anyone who is into this that can give me some pointers? I'm not a sadist myself, and I indulge his masochism because it pleases him so much, so I'm a bit at a loss of what to do beyond telling him to snap the rubber bands on his cock or add more clothespins.