Plenty of good advice already.

My boys are 18 months and 4 days apart, I BF DS1 during my pregnancy a, towards 34 weeks his feeds were shorter as I think supply stopped but he continued, once DS2 born I would feed him first then DS1 and did feed both at same times as well, and this continued till just before DS1 was 4 years old when he suddenly couldn't suck at breast anymore. DS2 is now 3 years 4 months and still BF.

I loved the experience of tandem feeding they would feed and hold hands so sweet.