Thought is was fun, so here you go: 1+2+3+slip/block jab+2+roll under jab+2 Starts with the basic jab+cross+hook, bring your lead hand to your face and move your head to the right to slip the incoming jab, counter with a cross, duck and roll to the right under the second incoming incoming jab, counter with another cross (or uppercut if you want) Took me a min to get it, but once I did, was very cool. Mitts are always my favorite part. So much more work than just hitting the bag.
When you are hitting the bag you should be slipping, blocking, moving in, turning angles, and getting out. Not just punching.
I would guess he would counter with a left (assuming he was orthodox). Veryl likely a jab to create some distance or set something up. Could be a lead hook. Either way, the drill could be good. Add the hook instead of the jab and roll with it or block it, then just continue the rest.