#and/or advice on how to do that sewn bind off properly if this is user error

[makerandbean]

urghhhh i just finished this very cute cowl i was knitting, and bound off using the bind-off they recommended as being nicely elastic (sewn bind-off; p2 on the needle, k1 off the needle). instead, it’s just loose, and the top edge has kind of mushroomed as a result:

i’m going to have to rip it out and redo it (including probably doing back a row or three of ribbing because the yarn will be messed up). blergh.

anyone got any idea for good elastic bind-offs that are actually elastic, rather than just Loose?