To move something around in the mouth and work it with the tongue and lips in order to take in its flavor or dissolve it, without biting it.
example
Das Kind lutscht genüsslich an einem Bonbon.
The child is happily sucking on a piece of candy.
Usage tips
Context clue
The three meanings are clearly separated by context. The neutral meaning refers to edible things, the colloquial one to a bad situation, and the vulgar one to a sexual act.
EXAMPLE
Ich könnte stundenlang an diesem Eis lutschen.
I could suck on this ice cream for hours.
Sentence structure
In the basic meaning, the verb is used either with an accusative object or with the preposition 'an' + dative. 'An' is used when you are only sucking on the surface of something.
EXAMPLE
Das Baby lutscht zufrieden an seinem Daumen.
The baby is contentedly sucking on its thumb.
Register and origin
The meaning 'to be very bad' is a direct borrowing from American English ('to suck'). It belongs to youth slang and is very informal.
EXAMPLE
Ich finde, der neue Film lutscht total.
I think the new film totally sucks.
Register
In the sexual meaning, 'lutschen' is a colloquial expression and is often perceived as vulgar. It should be used with great caution, as it can quickly come across as offensive.
EXAMPLE
Er wurde wegen seiner vulgären Sprache kritisiert.
He was criticized for his vulgar language.
Compare with
near_synonym
lutschen vs nerven
to annoy
'nerven' and 'lutschen' can sound similar in very colloquial language when something is bad or annoying. 'nerven' is the normal and clearly more neutral word for this. You can use it in many everyday situations. In this use, 'lutschen' means roughly that something is very bad or annoying, but it sounds very slangy and can also come across as crude. That is why it fits better among friends or in youth slang, not in polite or official situations.
lutschen
Der neue Stundenplan lutscht, weil wir jeden Tag sehr spät Schluss haben.
The new schedule sucks because we finish very late every day.
nerven
Mich nervt es, wenn der Bus jeden Morgen zu spät kommt.