It's nearly impossible unless you HO. The truth is you never know where the enemy "really is" so you can't intentionally ram 'em. You can try to guess, but really, it was an accident. HE probably didn't ram you on his end, if he took no damage.
I've done that before, where I make a close call (I don't ram, but it was close) and due to lag my lag position and the bombers' on their end passed through each other. I don't take damage, but the bomber might (hard to tell sometimes). On my end I didn't intend to ram, and didn't try to, but on the other end I did.
So, no, there's no real way to "intentionally ram" somebody. Just too hard to predict when/where to do it.