sexual practice vs sex activity

sexual practice and sex activity both are nouns.

Word	Noun	Adjective	Verb	Adverb
sexual practice	Yes	No	No	No
sex activity	Yes	No	No	No

As nouns, sexual practice and sex activity are synonyms defined as:

sexual practice and sex activity: activities associated with sexual intercourse

Other synonyms of sexual practice include sex, sexual activity.

sexual practice (noun)	sex activity (noun)
activities associated with sexual intercourse	activities associated with sexual intercourse