"Je veux te baiser" would sound unambiguously vulgar: "I want to fuck you". The common verb for kissing is "embrasser". "I want to kiss you" would be rendered as "j'ai envie de t'embrasser" or, more assertively, "je veux t'embrasser".
The word "baiser" can also mean "*a* kiss" (not to kiss), as in "faire un baiser", "donner un baiser", etc.
You might see "baiser" used as a verb in more literary (and perhaps antiquated) language, as when Jesus "baise les plaies" (kisses the wounds) of a poor man.