Subsequently to this post, I created a finished version of this picture myself, using Tom's composition and shading style, you can see it posted in 'Bar Predators Revisited'
There are other clues in this picture that it may have been intended as a longer series. The other bar users are beginning to join in. The sailor in the background looks like he's going for that rear zip we saw earlier, while another helps out with the biker's jeans. This has all the makings of a typical Tom orgy - which would explain the earlier involvement of the bartender. Are there some lost drawings here? Is the incomplete drawing the point at which Tom stopped working on it? We'll probably never know what really happened, but I'm happy with the series as it is, orgies are not my style and this forceful seduction is highly erotic - even if there's no coup de grace.
Update - January 2015
I recently discovered what seems to be a further picture from the series, shown below.
A cop breaks up the party, the only question is who's he going to nail?
See the whole story of how I identified this sketch as part of this series here