Splitting-a-bamboo
Position is one of the many sex techniques listed in Kama Sutra.
In this sex technique, the woman lies back places one of her
legs on her lover's shoulder and stretches the other leg out,
and then reverses the procedure, placing the stretched out leg
on the other shoulder and bringing down the first leg, stretching
it out, and so on alternately.

This
procedure is known as splitting a bomboo and requires great
concentration to perfect.