You drink the lime juice first and hold it in your mouth. You then shot the Bailey's and swish them together in your mouth as though you were using mouthwash.
Within several seconds your mouth will be full of a rancidly textured ball of goop (the "cement"). As a straight male I can't vouch for it but it must be similar to having a mouthful of cum. Swallowing it is even worse.
They are so gross that the clown who buys you one of these is lucky if you don't gob it back in his face.
Better choices can be found in the tags below.
George: CEMENT MIXER!