It means to make-out voraciously. Term is used more when people see you doing it publicly. Not necessarily a bad thing but people say it more disparagingly.

Referring to women who are sexually or romantically attracted to other women. Applies to both lesbians and bisexual women, as it is only the same-sex attraction that matters, not any other attractions the women may have.

Originates from the Greek poet Sappho, a bisexual woman from the Isle of Lesbos, from which we get the term lesbian.

hardcore making out. Lots of tongue action

suckface a non vulgar less offensive way of calling someone a fuckface when fuckface is not appropriate and profanity is not wanted

to kiss for a long period of time, may include (hopefully) some biting and licking of the neck and ears. non-pretty way of saying make out.

making out, kissing excessively and heavily

To kiss so hard/intensely that one or both partner(s) are literally sucking each others faces