There are numerous synonyms for the phrase "has sexual relations," varying in level of formality and connotation. Some more formal synonyms include "engages in intercourse," "performs coitus," or "participates in copulation." Alternatively, some less formal or playful synonyms may include "gets it on," "does the deed," "romps," or "hooks up." While these synonyms may convey different levels of seriousness or humor, it is important to remember that communication regarding sexual behaviors should always prioritize clarity and mutual understanding between all involved parties.