Bugs(?): In regards to "More likely to use anal moves." it may be intended, but they do use the move even when fully clothed, which seems off. Additionally, even after defeating the opponent who grabs you you can still fail escapes.
Future Update Recommendations: Make it so that only the one who grabbed you uses Anal Moves, but in exchange they always use those moves. In conjunction, make it so that when pinned each body part can be "occupied" by a specific enemy who will continually target that part and avoid others. For moves that directly stimulate the enemy (Anal/Oral/Footjob) it increases arousal efficiently, but when they become exhausted they can exchange their slot, including the grabber if they took the Anal slot, with possibly a turn skip if there are no non-stimulant slots available to wait-out their exhaustion. This way, it gives the impression of Ryouta being, positioned, passed around, and turn-taking rather than a chaotic pileup. Finally, add that if Ryouta defeats the opponent who grabbed him, if not recovering (preferably 100% chance) before enemy actions then enemies will try to grab.