The 2nd Barrell

I haven't been firing a second barrell and it has cost me. Two examples:

1. Pocket Jacks: http://www.pokerhand.org/?578077

I should either fold on the river or bet like $10.00 on the turn. In the long run, it would save me money. If he re-raises me on the turn, I know I'm dead. Otherwise he folds. I look his bet as sensing my weakness and trying to buy it. Horrible call by me.

2. Pocket Sixes: http://www.pokerhand.org/?578083

If I fire again on the turn, he probably folds. He played really loose (34/6) and would just check-call.