I played a hand live recently where I lost most of my buy-in:
It's 5-handed, £0.50/1 blinds, I have about 80, opponent has about 60. He is CO, I'm BU.
I had A 
4 :club:, and raised to 4 after UTG and the villain just called. BB and villain call, making the pot £16.50.
The flop comes A 
4 3 
Two checks to me, I bet £12, BB and UTG fold, villain calls.
Turn is 3 :club:.
Villain checks, I bet another £15, and he calls.
River is 9 :spade:.
Again villain checks.
Here I make a blunder and bet £12, and he goes all-in and I call. He turns over K 3 :diamond:, with a missed flush draw but catching trip threes on the turn, so I lost most of my stack. I know that the bet on the end was a disaster, and that the situation is crying out for a check behind from me, but I am interested in whether the cutoff's play was good, calling on the flop. Does this kind of thing (calling a big bet with bottom pair and a second nut flush draw) happen often?
I think You should isolate much bigger than 4x after 2 limps. My preferable line would be to raise 6x, cbet big & jam Turn. And when swear all over the table: "How could You call it..