With any of the one-handed grips, your other hand ought to be doing something other than just sitting there. Unless you're using it to turn the pages of a magazine or typing online (and if you can type one-handed while masturbating, I'd just like to say "Wow!"), you might consider giving your testicles some attention. They're very sensitive, as I'm sure your aware, and while for most guys that sensitivity is usually most apparent as pain, the testicles and scrotum can generate plenty of pleasure, too. Just about anything that feels good is fair game, but light touching, stroking, brushing, cupping, and gentle tossing are good places to start. During two-person intercourse your testicles would normally come in contact with your partner (depending on the position), so I've always thought of fondling them during masturbation as adding a touch of realism. For some hands-free testicle attention, check out the Scoot-Thrust.