anyone have success bf'ing morning/night & formula during the day

browneyedgoil

my friend is a teacher & never had time to pump while at work so she does this. i'm thinking of trying this after 6 months but how does your body know to only feed in morning & at night? 

 anyone have success doing this? did it ruin your supply? my friend has been doing it for 6 months but i'm just wondering if she is not the norm.