My best attempt to translate:

律子はエロいの！
ritsuko ha eroi no
Ritsuko's erotic!

りっちゃんはエロいと昔から思ってたよー
ricchan ha eroi to mukashi kara omotteta yo
I've always thought Ricchan's erotic!

エロいって言うの禁止！
eroi tte iu no kinshi!
Saying erotic is banned!

That only took me ten minutes of looking up kanji and thinking about grammar. What am I doing with my life?