Ok I am in the CO with 66, the SB and MP I have no read on.

$100 NL, .5/1

1 limper to the MP he raises to 4. I call, the SB calls , the BB calls and the limper calls. pot = 20.

Flop = 345 rainbow, the SB bets 10. the MP calls, and I call.
First Q: poor call? Pot = 50

Turn = 6, makes a spade draw.
The SB now bets 20, MP calls, I figure my hand should be good, barring 77. So I called, coupled with the fact that I can fill up. pot = 110.

River = 8, the spade draw misses. The SB checks, the MP goes all in for 18, these odds are too good to pass, however I just called. would anybody raise here? The SB had about 60 left.
In any case I just called as well as the SB.

pot = approx 164.
So I have 66, what do the SB and MP have? Results on the way..........

I think this is one of those situations where the only thing a raise does is make a better hand call (or reraise) you. Also by just calling..if you do have the winning hand, you made the sb call as well with his high pocket pair...where as he would have folded to a raise.

SB has a high pocket. MP has lower trips, very possibly the straight.