Breastfeeding is an incredibly special bonding experience between you and your baby. Why would you want to share that with anyone else besides your little one? Plus, swapping boobs might confuse him. He is used to you-your smell, your voice, your shape and size, and even the taste of your nipple. He may not want to suck from another breast; if he does try it, he may not want to go back to yours. Also, many drugs, both legal and illegal, alcohol, and some infectious diseases (like HIV and TB) can be passed through breast milk to your baby. I personally would not trust anyone else to feed my baby. Especially a friend who would make a suggestion like this-she sounds nutty!