breast feeding HELP!!@

im having a boy im march and i have a 5 year old daugther and a 8 year old step son. i dont know how to explain what im doing or about the female body and or letting them see me breast feed period. i asked my husband about step son knowing about it and he said he dont want him to know about it tell he aleast 11or 12 .. but my issue is since im a stay at home mom due to physcial issues how am i go to keep him from.being around like im have to stop doing homework and go nurse but then if im cooking n he helping im have stop letting him help and make him go in a room and stay tell im done or ima have a to stop cooking and go nurse and if we in public how ima nurse if i got him and the baby i cant hide in no bathroom and leave him alone and if cover up but still questions be asked.... so how do i handle this before the baby comes ? any ideas to explain or ideas to help ?