I know, strange isn't it? I have no satisfactory explanation. I know that 'baiser' as a verb, when followed by a direct object in a strictly formal sense means to kiss, as in;
"Je voudrais bien vous baiser la main" - I would like to kiss your hand. However,
"Je voudrais bien vous baiser", is likely to result in a resounding smack across the chops.
I always figured it was some kind of colloquial use which then fell into more usual, if not polite, parlance.
I remember being warned of the dangers of using it as a verb while studying french by a rather embarrassed french teacher although probably better than the alternative.
I remember a male friend trying to sayto his host family on an exchange trip that he was full after a meal and ended up announcing he was pregnant.
I also remember a rather unfortunate incident in a fast food restaurant in Spain with a bit of a mix up over the word chicken.