I swear DS knows there is a sibling in my ute and is trying to kill it.  He's constantly jumping on me/sitting on me/etc.  I try to stop him and redirect or move him to sit beside me.  At what point could this actually hurt the LO? Right now baby is tiny and there is a lot of padding so I'm not worried but just curious at what point it would be more concerning.  
He also keeps hitting/knocking/kicking my boobs.  Ouch.  I keep thinking how much more that will hurt after the baby is here and my milk is coming in.  The rock hard porn star boobs the first few days were so sore I couldn't even sleep on my side.  
Also, this post sounds like my kid is violent but it's all accidental - he just likes to be close to me (and my H).  He's a snuggler.  Exhibit A:
                
                
M/C 7/8/12
Perfect baby boy born 7/8/13
BFP 8/20/14 EDD 4/27/15 It's a GIRL!!
 
 
        
Re: BTDT moms: kiddos jumping on the belly
But I think it would take a lot to injure the inside baby at any stage in pregnancy (they are well protected in there). I would just remind your son to "be gentle with mommy." As you get bigger I'm sure he'll be able to remember more easily.
He's only 15 months so I'm not sure he will understand me saying there's a baby in my tummy, but I will try the "be gentle with mommy" approach and see how it goes. Good to know that it's not something to worry about re: it hurting the baby, even later in the pregnancy.
M/C 7/8/12
Perfect baby boy born 7/8/13
BFP 8/20/14 EDD 4/27/15 It's a GIRL!!
Factor V Leiden Homozygous, Advanced Maternal Age
TTC #1, 5 yrs, PCOS, Femera + Ovidrel.
IUI#3 BFP, DD 5/31/2012
TTC #2, 2 yrs, PCOS, Femera+Ovidrel
IUI#2 BFP!