"Frotting" is a term used to describe the act of rubbing or grinding one's body against another person or an object, usually for sexual pleasure. In this context, "frotting-cocks" refers to a specific type of frotting where two or more people are rubbing their erect penises together, often with the intention of achieving orgasm through friction and mutual stimulation.
This act is typically performed without any penetrative contact between partners, and can be enjoyed as a non-penetrative alternative to traditional sexual activities. It can also serve as a form of foreplay or an additional element in a variety of sexual scenarios. The term "frotting-cocks" specifically highlights the focus on rubbing together of erect penises for sexual pleasure