In the animations folder there should be a subfolder called 'info', this will contain XML description files for all the main-menu animations, within each file are all the subposes for each animation, including the Variety Pack subclasses, and near the bottom of each subpose entry should be a few lines that say 'ExcitementModifier'
I've been playing around with the 'CumEmit' ones myself, trying to get non-blowjob poses to cause the guy to cum, or for splatter to appear on the girl, but it doesn't work :p