An act commonly conducted by door to door sales people, especially frequented in the kitchen fitting world (Space Kitchens are innovators in this field). This usually happens as a direct result of rejecting their sales proposal. The indignant and humiliated rep will then feel the need to ask to use the home owners bath room and secretly urinate on the owners tooth brush or insert it up their anal passage before replacing it
See definition of Toothbrushing
an act of oral copulation in which a person has their teeth forcibly scrubbed, in the manner of a toothbrush, by another's penis
She wouldn't open her mouth so we ended up toothbrushing
the act of firmly placing a tooth brush in a clamp and sitting on the toothbrush and proceed to move up and down thus cleaning your anal cavity.
I just finish tooth brushing my asshole