....I gotta say, dear Frotter, that I was somewhat bemused by your handle, from the start.....
Comes from the French meaning 'to rub'

Like, all the cleaning products in the supermarket have the phrase 'sans frottage' ....no rubbing (sounds like my old school!!)
heres the reference:
rub [rab] verb — past tense, past participle rubbed
to move against the surface of something else, pressing at the same time
Example: He rubbed his eyes; The horse rubbed its head against my shoulder; The back of the shoe is rubbing against my heel.
Chinese (Traditional): 磨擦
Czech: třít se, dřít se
Danish: gnide; gnave
Dutch: wrijven
Estonian: hõõruma
Finnish: hieroa, hangata
French: frotter
German: reiben
Greek: τρίβω, τρίβομαι
Hungarian: dörzsöl
Icelandic: nudda, strjúka, núa
Indonesian: menggosok
Italian: strofinare
Japanese: こする
Korean: …을 문지르다; 맞스치다
Latvian: berzt; berzēt; berzties
Lithuanian: trinti
Norwegian: gni; skubbe; gnage
Polish: trzeć
Portuguese (Brazil): esfregar, friccionar
Portuguese (Portugal): esfregar
Romanian: a se freca
Russian: тереться
Slovak: trieť sa, šúchať sa
Slovenian: drgniti
Spanish: restregar, frotar
Swedish: gnida, gno, gnugga, skava
Turkish: sürtmek, ovalamak
But being French, has a whole load of baggage with it

So now we all know.
Cheers
TP x