I just go with the flow. Some games are very erotic but not sharp enough to get me over the edge, or I run out of content and have to find something else to finish with.
I personally find it hard to wank to games, but it can be a bit like "edging" for a good porn wank later. I guess there's a third option which is that you really are just in it for the love of the story. Either way, I do love playing these games.