most shopping centres have nursing rooms now, but if you cannot get one, then you can always go to a coffee joint to sit down and bf. you can use a nursing cover or wear a belly band under your shirt.
here are some of the ones that i have used:
vivocity - bad. nursing rooms are hard to find, small, poorly lit and poorly ventilated.
anchorpoint - nice. nursing area has 2 chairs that can be curtained off from changing area, but there is no centre curtain in between the two chairs. however, this means my hb can wait with me in the nursing area if the other chair is not used.
jurong point - not very good. nursing room is located inside female toilet, which means daddy cannot bring baby to change diaper. also means nursing room has toilet smell. they also have a basement baby room but it only has changing area with no nursing area.
taka - nursing room is located in b2 toilet, but there is no signage outside to indicate. there are individual cubicles with a locked door, separate from changing area.
centrepoint - baby room in 3rd floor is very nice and comfortable. nursing area is a big cubicle with a door, can seat 2-3 mummies & babies. there is also a family toilet on 6th floor which has a room for changing and nursing. no comfy armchair, just a normal chair (like those found in waiting areas).
harbourfront - nursing room on second floor is cosy with separate areas for nursing and changing. however, nursing area has a curtain instead of a door with lock. not so good.