When a male, in this case highly likely to be a virgin, is having sex and is unsure where everything is quite supposed to go, he may simply freeze in a pencil shaped position, head tilted slightly to the side, whilst the lady manouevres herslf on top of him. This particular act is highly unusual, but somewhat effective, and gives the impression of being stuckin a coffin.
If a young man has no idea what to do in the sack, it is almost guaranteed that he may freeze and will almost certainly be doing 'the coffin' , even if he does not realise this. Beware though, for the older you are before you pop your cherry, the more you'll look like one of Dracula's victims.
by Captain Coffin May 5, 2006