Presuming we are using the Yoga Sutras as a reference, knowing full well that one book alone does not comprise a complete system AND that an adherence to only one book is the foundation of dogma (“beware the man of only one book”)…
There are three relationships addressed; the one with self, the one with others, and the one with cosmos (universe/planet/environment). A relationship only with the self deprives a thirsty world of the light manifest through the inner work. A relationship only with others (without any inner work) is a hollow, transient existence, cording with others, sucking their energy.
If your friend is actually asking about sex then it’s an oddly round-about, though all too common way of getting to it. And my response there would be that yoga can help one to be more available in their living but it is not intended to improve your sex life any more than it is intended to reduce fat.
And again I wonder how many people distort the genesis of their “benefits” as being the result of yoga when perhaps they may just be the result of physical exercise and the subsequent effects on the body’s systems.