TAG reg keeps minraising me in position

[RunDownHouse]

This guy multitables and is 27/20/4 over 100 hands. He sits to my left.

At least half of the time, he's been raising my 4BB opens to 8BBs. Its generally been in late position, but that's because I do more raising from late position.

Once I flat called and c/f'd the flop, once I flat called and c/r'd him pot size, and once I flat called and donked the flop (which he shoved).

Obviously the better my hand, the easier it is to play. But if I'm opening AJo in MP and he does this, its really frustrating. Do I start 4betting light? That sounds like a disaster, but its probably cheaper than c/r'ing air more. How do you guys adjust to this?