frottage

n.

1. The act of rubbing against the body of another person, as in a crowd, to attain sexual gratification.
2. 1. A method of making a design by placing a piece of paper on top of an object and then rubbing over it, as with a pencil or charcoal.
   2. A design so made.

[French, from frotter, to rub, from Old French froter.]

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1) the technique of taking a rubbing from an uneven surface, by rubbing graphite over paper laid on top of the rough texture
2) the practice of obtaining sexual gratification by rubbing against someone, both parties usually being clothed