To prevent my commands from being logged to ~/.bash_history i use set +o history. The problem with this approach is that i can no longer navigate the command history with up/down arrows. A better solution is to send all history to /dev/null, just before exiting the terminal:

tmp_history() {
  echo "Commands in this session will not be logged"
  trap "export HISTFILE=/dev/null" exit
}

It works like magic.