A rare situation that
may occur where a couple involving a sexual intercourse using either the missionary posture or the woman-on-top posture.
When using an excessive
force, shaking the bed and banging the walls, an artifacts placed on
the wall (such as a picture) or otherwise on furniture,
may fall on one of the sex participants.
A situation where the couple proceeds with the intercourse regardless of the hit, is called 'headframe'.
The name origins is in a real-life
case where a male, while on top of the woman (missionary posture), was hit with a wall-picture. The picture itself smashed, but the frame retained on the male partner's neck till the end of the intercourse.