This is something that I've been doing lately that has been harboring some good reactions:

With any exchange of objects try to make it so your hands touch in the process.

Here are the two ways:

Object to Receiver - This one is where you hold the object in a way that has to be obtained by touching your hand. EX. You hold a card by the front end so that most of it is in your palm (small object in general are good for this), if an object has a specific hold that's good for holding it (like a handle) then offer them that spot.

Usually when I start to give it to them, I give the slightest brush and pause to their touch.

Object Back To Origin - Them giving it back to you. What I do is make sure it looks like I'm oblivious to the fact that I'm touching their hand. While I'm taking the object, I'll keep conversation going while giving them eye contact, or perhaps I get distracted by something else and my eyes pay attention to that WHILE I'm taking the object back from them, it just so HAPPENS that I ACCIDENTALLY touch their hand or grab the whole thing by MISTAKE.

Also I wouldn't do it all the time, they could catch on. Just once in awhile is good enough, because of course there's other ways to kino.