sex activity vs sexual practice

sex activity and sexual practice both are nouns.

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

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

sex activity and sexual practice: activities associated with sexual intercourse

Other synonyms of sex activity include sex, sexual activity.

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