Also known as: イラマチオ, イラマチオハンドル, イマラチオ
A form of Fellatio in which the person actively thrusts their Penis into their partner's mouth. Also known as face fucking.
The distinction between Fellatio and irrumatio is based on who is actively moving: irrumatio means to thrust the penis into the partner's mouth, while fellatio means to move the head and mouth up-and-down around the penis. For Tentacle Sex, use Mouth Insertion instead.
The word comes from the Latin irrumāre, which had the same definition; although to the Romans it specifically connoted non-consensuality, which is not always the case in English.