sex activity vs osculation

sex activity and osculation both are nouns.

Word	Noun	Adjective	Verb	Adverb
sex activity	Yes	No	No	No
osculation	Yes	No	No	No

sex activity (noun)	osculation (noun)
activities associated with sexual intercourse	the act of caressing with the lips (or an instance thereof)
	(mathematics) a contact of two curves (or two surfaces) at which they have a common tangent