How do I stop these romantic feelings toward my therapist?

It's a very common phenomena for clients to develop feelings for their therapists. Its called Transference. Technically it is (and I paraphrase) 'the redirection of feelings and desires and especially of those unconsciously retained from childhood toward a new object'.

Maybe once you understand the origin of your feelings, they will go.

Tell him your true feelings!

Tell him/her you are having those thoughts

Ask her to hold you down and suck your cock

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