My mother acted the same way when she got her Mother's Day gift.

Sadly much as we love Kanmusu being astonished by technology, this doesn't qualify for the pool because there's no indication that either of them are confused by the smartphone.

The context seems to be that Ryuujou is teaching Houshou to use LINE, a reference to this artist's series where she has trouble posting and thus, could only use stickers to reply.