Great pic!!
To break his pride, I think making the hero beg on his own will is very effective, especially in front of so many normal citizen. For example, the monster can keep stimulating the nipple and the asshole while stopping him from cumming. Ultimately, the hero will not be able to endure the pleasure and start beg for cumming. The fact that he begging willingly in front of normal people is destructive to his hero pride.