Hilariousness of the pic aside, I can't figure out what the first line is. "The bed's so {musu}"? Unless that's not a mu... Not sure about the "げきまおー" near the bottom either.
I don't see any better options than 蒸す. "It's so hot in the bed...", and then she goes right for the cup for some refreshment. げきまず is げき+まずい
Ah~ I'm so thirsty...What IS this?*spew**gulp* *gulp*Eh...Eh?Ehhh!Ai Love Yuu [I Love You]
鉄 means "iron"; it's not normally pronounced "ai", but it is in Aiko's name, which is written 鉄子
油 means "oil", and can be pronounced "yuu"The bedroom's so hot~