Mango says they have something called the erection system, which lets you use your stand-to-pee packers also as a hard pack. It slices, it dices, it pees, it penetrates. Sounds awesome.
What I think would be a nice feature for dual use packers is a size change. A biodick swells up and ideally, a packer should too. Using fluid for this trick is probably not a good idea, so that leaves two alternatives that I can think of. One is to find a material that swells when exposed to a small electrical current (any suggestions?). The other is to use air.
Over my winter break, I plan to do an experiment with air: I will fill a condom partly up with hairgel. Then, I will take another condom and put a pencil in it, eraser side down, and push that into the gel. Then, I will glue the two condoms together with glue that is stretchy, water-tight, and non-toxic (got any suggestions for glue?). After removing the pencil, I want to keep multi-bagging the hairgel condom in the normal way, but always leaving the opening to the inner condom. Finally, I want to glue a tube in there and attach it to a small pump. I think for testing purposes a water gun will do, but something that would fit in a ball would be even better. My hope is that inflating the inner condom will cause something like a hardon. A small squishy packer becomes not so small or squishy.
If you've heard of anybody trying this, I'd like to hear about it. Otherwise, I'll report back on my mad scientist experiments after I've managed to try them.