My favourite CHAI record.
Piecing things together as best I can. I don't know Japanese.
わがま is what I'm not sure about, and Google Translate and DeepL have several translations, 'Selfish' seems to be the one common one.
マニア is an English loanword, 'mania'. Apparently the usual meaning in Japanese is a person who is enthusiastic about one thing in particular, though it's a little different to Otaku.
So I think a translation would be 'My (or Our) Obsession'? But I think I'm missing some nuance here. My first thought was it could be 'Self-obsession', so maybe that's a valid option too…