It looks like he's protecting a hand against a slightly scary board, if he's thinking he may wonder why you haven't done the same. For this reason I'd normally just raise the flop. Whats your plan if pisces folds and you face another PS bet on a blank turn?

If i'd seen you get aggressive with draws in the past I think I'm calling with any decent A as you line dosent really add up. I don't think it matters too much though as a push will still get enough folds, and with a pair as well you equity is so good I still think its +EV.