I understand why she has the gag, but why a bit gag specifically?

Saladofstones said:

I understand why she has the gag, but why a bit gag specifically?

I think the intended joke here is that Nezuko was placed under a subtle hypnotism(?) so that she sees all humans as her family (not just her brother Tanjiro), therefore must be protected from harm. She did exactly this head-patting gesture to a human stranger in earlier episode before fighting to protect them from other demons.

In short, Nezuko here still sees Doomguy as a human being worth protecting like one of her own, whereas Doomguy himself can't bring to slay a demon this harmless and kind.

Soviet Russia, Nazuko headpats YOU!!

*Heavy metal music stops*

This is so cute. Alexa, play This Love, by Pantera.

Saladofstones said:

I understand why she has the gag, but why a bit gag specifically?

Think it might have to do with the setting. A bit gag made from bamboo is easy and readily available in case of a new one being needed.

I don't know about any of you, but I don't think this is going to end well.

matteste said:

Think it might have to do with the setting. A bit gag made from bamboo is easy and readily available in case of a new one being needed.

That and bamboo having almost the tensile strength of steel alloy, so nezuko can't easily bite through it.

Frawnkenstein said:

I think the intended joke here is that Nezuko was placed under a subtle hypnotism(?) so that she sees all humans as her family (not just her brother Tanjiro), therefore must be protected from harm. She did exactly this head-patting gesture to a human stranger in earlier episode before fighting to protect them from other demons.

In short, Nezuko here still sees Doomguy as a human being worth protecting like one of her own, whereas Doomguy himself can't bring to slay a demon this harmless and kind.

“Nezuko here still sees Doomguy as a human being worth protecting like one of her own”
Even after godly upgrade he received?