Used when a character masturbates two of the same sexual organ at once, mainly a character using both hands on their two_penises, but could also apply to the rare cases of characters with multiple vaginas

It is NOT relevant if the two organs are not a pair, for example, combining anal_masturbation with penile or vaginal_masturbation, when the owner only has one of each. Double_fingering may apply in that case, if both orifices are being fingered

See also:

masturbation
double_fingering
mutual_masturbation
multi_genitalia
two-handed_handjob