Materboating is an alternative version of motorboating. It’s when you motorboat multiple people at once, or when you want attention and try to get it in the worse way possible.
It means the activity of putting one's face between a woman's breasts, and rocking turning one's head rapidly from side to side while making a noise like a motorboat.
"Put your head between her tits and go bbl bbl bbl bbl bbl..."
The placement of one's face, specifically the mouth, into the area between a well-endowed woman's breasts, followed by a rapid shaking of the face in a side-to-side motion accompanied by yelling. The resulting sound that is created sounds similar to an outboard boat motor.
Sherry was wearing a low-cut top and Mike approached her and started motorboating in her cleavage.
The placement of one's face, into the cleavage of a man's moobs, followed by the side-to-side shaking of the head accompanied with a motor-ing sound.
John made many trips to McDonalds on Friday; resulting in a hefty, yet delicious figure. Sarah was captivated by his rolls and decided manterboating his moobs at the pool the next day would be a hot idea.