Absolutely. Many couples enjoy e-stim together. You can use conductive pads on each other or use insertable toys. It is recommended to set a safe-word and thoroughly discuss boundaries before play.
Using a dedicated stim box is the only method that can guarantee safe operation. An article on the official ErosTek blog summarizes it best: "Stereo amplifiers are made to produce sound using speakers. The ErosTek ET312B was made to produce pulses that feel great when you connect them to your body. Nothing beats a device made to be used for the job it was intended." electro sex stimulation audio files full
Romantic e-stim audio frequently draws from popular romance and BDSM fiction themes to build its worlds: Absolutely