It probably had to do with the fact that he still had some reservations about it the first time. The second time, he had none, so it went fine.
Was wondering too, but I guess all the time they spent apart had him thinking, and he got over the shock and realized he actually does want and love Saya
I guess the first time it didn't really sink in that Saya is a man with his own bits. Yuusuke only thought him as cute and got off with his own imagination. He needed that shock to move on I suppose
He needed a condom and lotion maybe
Why was he okay with it this time, when he wasn't last time? Did it cover that?