Like the style of cocktail, in which a mix of liquor and flavoring are combined over ice in a tall glass, The Henry Lawson Highball is derived from the act of having sex with a woman who riding you "cowgirl style" proceeds to expel ejaculatory liquid from her pussy through orgasm. While this is going on, the intense pushing from the females pelvic region causes the mans bridge of skin from the head of the penis to the shaft to tear and begin to bleed at the same time as reaching orgasm and he himself ejaculating.
The aftermath involves the man being covered in female ejaculate, semen and blood on his torso and stomach, to which the woman mixes it together in his belly button and drinks it like a shot.
Last night I picked up that slut from the pub, mixed her a Henry Lawson Highball, it was intense! I had to wrap my dick in a towel for an hour after.