For the sexual intercourse sense, perhaps it derives from the obsolete meaning of shake or wiggle, which looks connected to shake itself. Look, we even have a quote of the shake sense (from etymonline):
- "And þe boot, amydde þe water, was shaggid." [Wyclif]
- (And the boat, amid (in) the water, was shaken.)
--Wytukaze 14:39, 14 May 2005 (UTC)
In modern day english shag is probably used more to refer to sexual intercourse than any of the listed definitions. And yet that definition of shag has been deleted. The Oxford Dictionary is more progressive than Wiktionary. —This unsigned comment was added by 22.214.171.124 (talk).