Bill could never tell Stanley he was majorly crushing on his twin sibling. Like, never. But he couldn't help trying to win you over, as nervous as he was about it.

He'd learnt more about Judaism in preparation for you and Stan's Bar / Bat Mitzvahs, just in case he needed to, I don't know, try impress you with his knowledge. Subtly, though; Bill knew the art.

"How– How are you f-feeling?" He chimed in as he walked his bike next to you. "You-You and Stan are gon– gonna be grown ups, now."