roll in the hay vs ass

roll in the hay and ass both are nouns.

Word	Noun	Adjective	Verb	Adverb
roll in the hay	Yes	No	Yes	No
ass	Yes	No	No	No

As nouns, roll in the hay and ass are synonyms defined as:

Other synonyms of roll in the hay include fuck, fucking, nookie, nooky, piece of ass, piece of tail, screw, screwing, shag, shtup.

roll in the hay (noun)	ass (noun)
slang for sexual intercourse	slang for sexual intercourse
	hardy and sure-footed animal smaller and with longer ears than the horse
	the fleshy part of the human body that you sit on
	a pompous fool

roll in the hay (verb)	ass (verb)
have sexual intercourse with