According to Wikipedia, cēvēre loosely means the actions of a female during intercourse, whereas crīsāre is the same but with anal sex. It later states however that cēvēre refers only to the actions of a passive homosexual man in intercourse. This is somewhat contradictory, so what is the difference?
Dictionaries are notoriously bad at describing sex acts. Thankfully, J. N. Adams rectified that with his The Latin Sexual Vocabulary (Baltimore, 1982). I can add little to what he says of the two words (p. 136–137):
(vii) Criso and ceueo
Latin possessed two technical terms for types of sexual motion (in both cases that of the passive partner), criso and ceueo*. Criso indicated the motions of the female in intercourse: note ps.-Acron Hor. Serm. 2.7.50 'idest dum ego iaceo supinus et ipsa supra me crisat'...The passage in ps.-Acron should not be taken as implying that criso was appropriate only to the schema with the woman astride.
Ceueo was used of the corresponding movements of the male pathic (cf. *ceuulus = 'pathic', CGL IL.357.20)...
Interestingly, he goes on to say that these are not very offensive words compared to something like futuo.