XP: Milk "dropping?"

jiffy-pop

I'm a STM and I remember the feeling of let-down during nursing. I've been getting that same feeling in my breasts the past couple of days. I keep checking to make sure I'm not leaking but nothing ever comes out, I just get that tingling feeling in my boobs like a let-down feels. Can milk come in or "drop" (seems like I've heard that term before) before baby arrives?