More details here~ When Eevee bites Green, he screams “あ–” “いてぇー” (a.. itee!) (ah… It hurts!) the first time, and “あいてぇー!” (aitee!) (ah it hurts!) the second time. Red, not seeing what’s happening, took it for a yelled “会いてぇー!” (aitee!) (I want to see you! / I miss you!) in the masculine way to speak. Green uses this way of speaking, and thus always finishes his sentences in “eeー” instead of “ai”, cause hey! the very great Green is a real man haha.