[Masquerade]

Don't limp-call unless you are specifically trapping someone. If you decided to play AJ then raise it. Just 2 x BB if you wish. Make others respond to the fact you've raised rather than just call/check by default.

Your friend's M is (1800/225) or 8. In general with an M less than 10 you should raise allin [unless wanting action with a monster] and it's imperative here with your extra 150 in the pot if he thinks you're limping with a marginal hand. No other play is correct here - you simply cannot put in 1/3 of your stack pre-flop and play post-flop correctly. You particularly must raise allin with a modest pair like 88. Raising 600 here is a terrible play. Folding is better. There is obviously enough money in the pot for you to call.

Post-flop you've caught second pair nut-kicker which is obviously sufficient to call an allin of just 1200 if everyone else is out. The SB calling makes things a bit tricky but if you read is that he is just a donk then his call makes it even more attractive odds for a call by you.