Quoting Betty Sue.:" My son is 3 years old, and is still trying to breastfeed. My milk dried up in September 2012, while we ... [snip!] ... of me, since he is always up under me and inside of my shirt. Any advice on how I can make it stop? This is driving me insane. "
This can happen when a child is weaned before ready & I have heard of other mommas having issue with longer term struggling with a child wanting to put their hand down the shirt. It would have been easier to rid this behavior when he was still nursing as you can use nursing as your bargaining tool - so you teach nursing manners in exchange for agreeing to let them continue. At this point, those behaviors would need to be addressed in accordance with whatever you do for *other* undesirable behaviors he does.
At this point, since you have weaned, there is no reason to address this as a "breastfeeding" issue since he isn't breastfeeding. This is like anything else he may do that you want to stop & treat it as such. Make sure you are giving him lots of attention & cuddles & then set up boundaries & stick with them. Persistence like this normally comes from you giving in some times & not others. If he does it more in front of others, it is being done to demand your attention at a time he feels can interject himself. Make sure you are meeting his needs for attention & then let him him know it has to stop & keep up with firm responses when he tries. As far as at night you will need to keep things wrapped up - so wear a bra & clothing that is snug & covering so he has no access until this passes. It WILL pass.