This actually was one of my reasons for writing the VN (sort of). Too often you see in VNs that these blushing wallflower MC virgins suddenly and magically take massive anthro cocks for the first time like their assholes were hither-to-unknown stargates. I always found it a bit misleading.
I wanted to show it with more realism, so that is why Corwan is a sexually active man. He has taken cocks before and knows what to do, how to prep, and what to expect.
That isn't to say he doesn't like topping too though as we have seen.