He can't.

If he had been Batman, he might have had the training and **** of will to supress the desires that were comming up from the sexual contact that Harley was giving him. But he didn't. Worse, his hormones were starting to surge as an eighteen year old, he was reaching his sexual peak!

So when Harley decided to take a ride on the Robin Cycle, he was helpless to resist the pleasure of the ride. As his cock went into her pussy, it felt loose. 'Good, with any luck, I should be able to resist a little by not cumming.' Tim thought as Harley started to rub her nipple against his lips.

Then the Pussy tightened. It was amazing that Harley was able to manipulate her vagina muscles to milk and massage the cock of her new, hesitant lover. Tim was starting to feel his arosual grow!