Hi! The title is the question.

My girlfriend and I are both Switches and have an excellent sex life. She naturally feels more comfortable in her dom, so I'm looking for techniques I might use to help her really relax into her sub. (She already plays in sub and enjoys it, so I'm looking to go a little deeper)

We have an interest in psychological games too. (Training, essentially) Romance, love, and "little girl"/daddy energies tend to relax her and immerse her the most.

Some effective and slightly hypnotizing positive reinforcement 'treats' that I already know work great are gentle petting, simple kisses, and words of affirmation,

What sort of punishments might work well considering that those are the 'treats'? The idea for the punishment is that it be effective, but not so intense that it knocks her out of the scene. (She does enjoy bondage & restraint)