In settings with more than 1+1 moaning feels nice as well, since participants have vocal feedback which might turn others on as well.

Suits (or organisms) that wrap around and are alive, often stimulating the wearer.

Soft Vore / Biosuit

Tickling

Fucklicking

Teasing / (Orgasm) Denial

Eye contact (between participants)

Pronebone with extremities tied

Two women chat while walking and one is thanking the other for taking her along to the gym - they proceed to a room with exercise bikes where another woman greets them while riding an exercise bike with a dildo strapped on the saddle. Thankful person is flabbergasted, but told not to be shy.