[mixmastermattyk]

grizy is spot on with this one in regards to either getting it all in on the flop or keeping the pot small. There are plenty of opponents who I know will want to felt with their trips with an A kicker and a couple of overcards (or sometimes even just the A kicker and one overcard to the board).

Underfulls are, for me, one of the most important hands to have a solid read on an opponent. The lack of a safe turn card, when any card that drops could perhaps fill them up, means that knowing what they're tendencies are is extremely important. Check-calling down really isn't my preference, as I find even the more passive types will fire more barrells at you even if they don't always have a full. If you know an opponent isn't particularly aggressive, a flop call will usually mean they've got trips or they might already have top full and be slowplaying. I almost always follow this up with a turn-bet of 1/2 to 3/4 pot, knowing this particular opponent isn't going to raise me without a boat. This will occasionally create tricky river situations as to whether they'll bet without a higher full but it seems to make it easier (against the standard more passive type opponent) if you show a decent bit of interest and let them know you do have something.

Aggressive, tricky opponents create a stickier situation when they raise you, meaning you're either getting your money in as a reasonable favourite or drawing almost dead but I haven't found too many good opponents who go crazy on a paired board without a solid hand - and the ones who can read me and push me off, well, that's what table selection is all about...

Bottom line, with an underfull, if it's a raised pot, I'll try and check/raise all-in (depending on stack sizes). In an unraised pot, I'll normally open-pot it and go from there (without trying to bloat the pot but still showing strength). Definitely one of the tougher situations in PLO though.