Thumbprint

[Monty]

A thumbprint is a method of consuming a massive amount of [lsd], where a massive (relatively, compared to a [blotter] dose) amount of lsd [crystals] are made into a small pile, pressed on with a thumb, and then the thumb into the mouth.

A thumbprint is, despite the large dose is not at a high enough level to reach levels of toxitiy in the human body.

[Britney]

An impression or mark made on a surface by the inner part of the top joint of the thumb, especially as used for identifying individuals from the unique pattern of whorls and lines.