Am I over-reacting to this part of the play or should it follow the book?

I have one of the lead roles in a play that is ready to open. In the play as well as in the book is trys to follow closely, the talented young girl who plays the lead must be given a spanking over my lap. I told the director this tests my manhood to be seen the way they want it. The little girl is in a shirt and white panty cause the spanking occurs at night. Is this necessary? In rehearsal with a small crowd they seem to like this and think it adds realism. Am I over-reacting?