It is best to treat Sengo like an unruly child and not give him the reaction he probably wants.

Ichigo keeps a smile on his face as he laughs a little more. "I'm afraid they won't be interested in that either, Sengo-dono."

Anyway, he's rather self-conscious about his scarred back, but he's not going to mention that nor let the slight discomfort he feels at that suggestion show. Let's try changing the topic instead.

"Hmm... perhaps it'll be better to bait them with food instead? I wonder what they like to eat."