My Soul is the Sky: How to Cut or Trim Side-swept Bangs - tried this today and it really works! Just pull bangs to the opposite side you want them to sweep to, and cut in a straight line. Works like a charm.
You don't want to go to a hairdresser and pay loads of money for something as simple as bangs, but you also don't want to go around with a bag over your head. Cut your side swept bangs correctly, at home, after you've seen this video.