The act or practice of engaging in sexual intercourse in which two men position themselves on either side of the female and proceed to commence the fornication while simultaneously slapping each others hand, thus resembling the Eiffel Tower. This act is usually accompanied by an energetic "Yeah Bro".
Those two kids were late to class because they were eiffeling that chick in the hallway.
A woman simultaneously receiving anal sex and performing fellatio, thus (assuming the males are standing and she is bent over) forming what could be considered to be an Eiffel Tower-like shape.
When under age boys and girls get together and do buttsecks and oral in an orgy-esque style. But it's not real sex. So they can still claim to be virgins.