Do you ever have an erection when an amazingly sexy woman passes by?

Yesterday, I was looking for a Taxi. While I was waiting, this amazingly sexy girl passed by. When I saw back, my penis instantly gave her butt a military salute. That was kind of embarrassing and I tried not to show people what's going on down there so I turned my face (and my penis) toward the other side (a wall). Finally, my penis calmed down (thankfully it didn't reach full erection).... Did this ever happen to you?