[Big_Jim]

First things first. If you can, sit on their left.

Secondly, start re-raising them PF when you want to play a hand against them. Do this with premium hands as well as average->bad hands. Don't do it every time, or they'll lose respect for them and start playing back even harder. (Although, this could be a good thing)

After the flop, be more inclined to take free cards and use pot control with marginal hands, and bet your big hands strongly, hoping they'll make a move.

LAGgy play works best when players are weak-tight and/or passive. It loosens up the table and makes these kinds of players very uncomfortable.