Well Google failed to offer me a definition, though searching for the phrase offered 6 inside a paywall - sulk...

I think it's something like: when the intention of one or both of the participants in a process of touch is to gain genital stimulation tending towards orgasm, then a genital relationship is happening - especially when it's the intention of both. But of course there are situations when it's not really clear, especially when the topic has never been raised by the participants. In the BL case, we may knowingly engage in more touch for ourselves than is really appropriate in the belief that our YF isn't aware of the genital component of the touch that is happening. Clark refers to one occasion when he got an erection because a cute young lady gave him a big hug after a sermon of his that she had really enjoyed; in retrospect he felt that this wasn't inappropriate because it wasn't his intention - and that's probably an important element for us to consider.

Does that make any sense?