kisama

Japanese has varying levels of politeness - this is the most impolite way of addressing someone. Could roughly translate as "bastard", "scum" etc.

Literally "precious sir" in Japanese ("ki" meaning precious, "sama" being a very polite honorific), it is what a samurai called his enemy. In modern speech, it can be used with someone you want to kill or as an extremely rude insult. Has been used by soldiers and yakuza. Sometimes used liberally by english-speaking otaku.

Japanese for bitch.

It is a term that shows affection. To be precise, though it's original form holds a different meaning, in urban usage it usually means that I'm going to kiss you. Of course it is mostly used as a figurative, but the situation in which it's used can unravel in face sucking.

The 'ama' is akin to the english "I'm gonna" , and the 'kis' is akin to the english 'kiss'.
Thus "ama kiss you" is an appropriate way to view the urban usage of 'kisama'.