Similar to a "snorkel" in which a tall man (a spaniard, for example) leads a much shorter man (e.g. a slavik dwarf) into the sea. When the water becomes too deep for the dwarf to breathe without swimming, the taller man forces the dwarf's head under water and shoves his cock in the dwarf's mouth, mimicking a snorkel. However, scuba diving requires an even taller man (a Pollock, for example) and a much shorter man (a Japanese man), and the two explore the deep crevasses of the ocean floor.
Especially effective if the Japanese man is only half Asian, as he will be less vindictive in the case of resurfacing.
Christian: Chris, would you like to go scuba diving in Gloucester?