・・・、。
I'll feed you, so… here, open wide.
Literal
I [subject-が] will-feed [because-から]... yes, aahn do.
Caring and intimate. 食べさせる is the causative of 食べる ('to eat'), meaning 'to make/let someone eat' — here in the sense 'I'll feed you.' アーン is the sound of opening your mouth for a bite, the Japanese equivalent of English 'say aah' or 'open wide.' アーンして ('do aahn') is the verbed form — a fixed phrase when feeding someone (lovers, small children, the sick). A warm, slightly embarrassing intimate moment.