So what the heck does うおォン mean? I can find citations of it on the internet, many but not all in context of K-on!, but I can't find anywhere reliable that gives me a definition. The mix of hiragana and katakana is odd, but I would guess meaningful somehow.
It's a reference to the manga 「孤独のグルメ」 (Kodoku no Gourmet). In Chapter 8, the main character is eating 焼肉 (yakiniku) and suddenly exclaims, 「うおォン、俺はまるで人間火力発電所だ」 (Uoon, I'm practically a human [power-generation] furnace!) Due to the oddness of the sound, it apparently became a meme.
First and second google results for "うおォン" are both relevant.
By the way, ゲン担ぎ (弦担ぎ) refers to a superstitious action performed as a good luck charm. Often used to refer to food, I think - like eating a particular dish before attempting to take an exam, or run a race, etc. I think she's literally trying to eat the string because Ritsu said that it worked for her in the past, or something.
*plink**twang* *twang*If I eat the string of a guitar as a gen-katsugi*, I'll get good at playing the guitar. I'll get good. I'll get good. I'll taste** ...huh?*弦担ぎ (gen-katsugi) is something you do (often something you eat) beforehand to improve your success at some task, usually because of a superstition.
**「上手い」 means "skillful", and 「美味い」 means "tasty". Both are pronounced "umai", hence the pun.Ricchan said so.Uown, I'm practically a human electric plucked string instrumentA reference to the manga Kodoku no Gourmet. See the Hatena::Keyword entry for this meme.RITSU!
What have you been teaching her!