How do you know when a breast has been drained?

[LaTristesse]

Just wondering really... I usually just keep feeding until it feels like a floppy sock and aches a bit, then I swap her over. But is there a more technical / accurate / correct way to do it?!

Check the measurements on the side?

What you are doing sounds fine. A breast is never truly 'drained' or 'empty'- these kind of terms are a bit misleading really. If what you are doing is working for you both then carry on!

Most mums find it works pretty well if they feed their baby from one side until he/she comes off and then offer the other side to see if he/she is still hungry.