Skeins of earthy, spirit-like verse

Hello Friends;

What is the meaning of "skeins of earthy, spirit-like verse" in this text and, more important, what is its relation to other of sentences?

Not coincidentally, this conduct often involves such a dramatic release of tension that master and student find themselves bursting out in stomach-knotting fits of laugher and skeins of earthy, spirit-like verse.

Thanks for your help.