pull a Sydney

intransitive verb:
1. To commit to purchase something from a fellow classmate, and then buying it from someone else
2. To be profusely sweaty in a cold room at 8 am

transitive verb
1. To screw one over

The wench committed to purchasing a t-shirt from me, but at the last minute, she pull a Sydney on me and bought one from another wench, leaving me out to dry ): !