Roddy had been with women of varying experiences level in his time - he was no stranger to the boudoir indeed. It was almost expected of pureblooded wizarding males, and his father had introduced him to the opposite sex at an early age. His father had even bought him a virgin once. He'd found her an interesting experience, although he wasn't as enamored of having to teach her what he wanted her to do. But he made do, as men are wont to do when they are being pleasured.
Even through the lust-filled haze that was his mind, he seemed to catch on that Bella was, for once, unusually reserved. At first, he worried that their present activities were not to her liking. But he knew that if she didn't want to do it, she would have flung him off and given him the rough side of her tongue. No, that wasn't it.
He slid his hand beneath her skirts, pushing them up as he traversed her thighs, until he reached her apex, tentatively stroking the area where her thighs met. Her pants seemed wet enough, so he couldn't doubt but that she was turned on.
He looked into her eyes as he began to insert one of his fingers, looking to see what her reaction is, before he did any more. He wasn't necessarily being patient, but prudent. His desire for her was a fierce ache that was centered in his crotch, and suddenly he was seeing his best friend in a whole new light.