I was thinking that maybe by developing your traits, new abilities could be developed, to either pleasure oneself or the enemy that had grappled you. This could involve the interaction with parts that you have developed traits on.
(Warning!!! Pretty Buns and Underthought Suggestion Inbound!!!)
I also was thinking that maybe it could be fun to be able to be the ones who grapple the enemy, I noticed that during grapple scenes, enemies use abilities to advance arousal, and I thought that you could use those abilities which you can gain via the earlier mentioned method, to possibly get rewards and exp.