The context: Yotsuba goes to the front door to welcome her friend, and says 「どうぞおあがり。おまかいですが。」and her friend visibly confused responds with 「何だそれ？」I didn't manage to find this おまかい expression on the dictionary or Google. Since she is a child, I imagine it may be a mistake, but then if so, what is the actual word she meant ro use?
It seems a popular phrase from that manga (enough to be merchandised), whereas you'll find many Japanese people wondering or asking what it means on Google.
So what it actually means is not immediately clear to me either, but it does sound like she jumbles up several (humble) set phrases used when inviting people to your home, like:
- お構いもできませんが "(sorry) that we can't treat you (satisfactory)"
- 狭いですが "that it's a cramped place"
- 汚いですが "that it's a messy place"
- お構いなく (what guest says) "don't bother yourself"
- つまらないものですが (giving gift) "though it's nothing special"
One of lines that contain this phrase is translated as follows, according to this article:
Ahem, welcome to our humble aboard! Step on up!
（どーぞ おあがりたまえ!! おまかいですが）