Implicating irrumatio → oral
Link to implication

Reason:

The definition from the wiki states:

A form of oral sex where an individual thrusts their penis into the mouth and/or throat of another.

Related implications:
irrumatio → penile
irrumatio → sex

I also believe that oral knotting should be de-implicated from fellatio and imply oral and penile instead as this could also happen with irrumatio.