Accidentally on purpose
Badger someone
Balancing act
Bare your heart/soul
runs away or goes back hurriedly to avoid a dangerous or difficult situation
one's best bet
you wait for a good opportunity to do something
you are unfriendly or do harm to someone who is kind to you
He blotted his copy-book when he was arrested for speeding.
On the bottle
Behave in a completely unacceptable way
someone's watching you too closely and making you feel uncomfortable
build bridges