You tell her that this is what happens to natural boobs when women get older or have children, and that this is perfectly normal and okay. Only plastic boobs stay permanently pert and upright.
lol i never told her nothing i was in shock as i had bein going on about it a few days before to my oh did have a laugh about it tho as she pushed them up and told me thats were they should sit it aint as if they are big