I've had a carbomb before... it sounds like yours but I think had another shot of something in it and was topped up with Guinness. Needless to say you had to down it tootsweet before the Baileys started solidifying.
I only did it as part of an initiation to the Cricket team's pissups. I'm not even on the cricket team, but my flatmate was. Needless to say I pissed all over it and took it out in one in about 15 seconds, tasted like yoghurt. There was someone who actually was starting on the cricket team who couldn't do it even in three goes... pussy.