stimulation vs necking

stimulation and necking both are nouns.

Word	Noun	Adjective	Verb	Adverb
stimulation	Yes	No	No	No
necking	Yes	No	No	No

As nouns, necking is a hyponym of stimulation; that is, necking is a word with a more specific, narrower meaning than stimulation:

stimulation: mutual sexual fondling prior to sexual intercourse
necking: affectionate play (or foreplay without contact with the genital organs)

Other hyponyms of stimulation include caressing, cuddling, fondling, hugging, kissing, petting, smooching, snuggling, feel.

stimulation (noun)	necking (noun)
the act of arousing an organism to action	affectionate play (or foreplay without contact with the genital organs)
mutual sexual fondling prior to sexual intercourse	the molding at the top of a column
any stimulating information or event; acts to arouse action
(physiology) the effect of a stimulus (on nerves or organs etc.)