gave them the middle finger

flip someone off, raise the middle finger in an aggressive gesture meaning "fuck you!" The raised middle finger suggests a phallus.

The driver was tailgating me, so when they passed me I gave them the middle finger.

Finger horn

Using your finger to get your feet into a pair of dress shoes, when the shoe horn is backwards and you are hammered drunk.

Derek was so hammed his shoe horn was back wards so he had to resort the the double finger horn