Ambush Hickey
Similar to a conventional hickey, except the suckee is not aware the sucker is applying suction until it is too late, and the deed has been done. Frequently occurs because the suckee is in the throes of passion and does not notice what is happening. Ambush Hickey may be placed either in a highly visible or hidden location, depending upon the intentions of the sucker.
She was so into what I was doing that she didn't notice the Ambush Hickey I applied to her {cleavage}. The next day she discovered the mark, and she had to wear a turtleneck for the next week.