I don't think the issue is that he was playing with yourself, spanking the monkey... the problem is that he was using her hand (without her consent) to spank the monkey. I'm not sure how you can justify this as being ok, but I can completely understand her feelings. No one... not even a woman's boyfriend or husband... has the right to engage in sexual activity with her without her consent. She had already told him 'no' to sex that evening and was not in a position to be able to consent at that moment (she was asleep). Therefore, his actions were completely inappropriate.