I drink club soda, which has the added benefit of being high in sodium (salt). The galvanic portion of the electro turns the water and salt in your tissues into hydrogen, oxygen which do nothing but 'bubble up',) and sodium hydroxide (lye) which is what kills the follicles.
I use betacaine (google it,) which has a petrolatum base and doesn't need the occlusive dressing. It also needs to be applied in a thick layer (I use a 'trowel' I made out of a plastic business card to apply the stuff.
Doctor-prescribed pain relievers can also help. But I'll leave it to you to consult with your MD as to which ones, what dosage, and what precautions you need to use. I ride public transportation to the electro on the days I use the prescription stuff, and either ride back or get Lisa to take me home.
But the benefit is that she gets to turn the juice up and get more hairs per hour than without. And we can go for longer sessions (up to four hours.) So it's actually saving me money. Again, work with your doctor, don't self-medicate!