Nothing really "crazy" crazy.
I told the story in the gwbyh thread years ago. Had a coworker, had a thing going with her, she decided to stay with her bf, met again 8 years later... and that's where the crazy fucking comes into play. She was always super fucking wet, and super tight. We fucked all the time every time. Short break, next round. Must have been 2003 or so.
Sadly that ended again and she stayed with her bf, only to be dumped years later.
Anyway, there's the other ex, 2001 I think. She was very into anal, sucked like a dyson, and nothing I could come up with was too much. To be honest though, I was young and couldn't come up with much besides oral/anal/cumplay. Freakiest was probably stand up sex in the shower with anal.
And then there's my later to be ex-wife, we had just broken up in 1995 but she wanted to fuck, so we drive to a place in the forest and I fuck her on the hood. Put some nice dents in my car. Finished, drove back to town, school lawn, round two.
Married her in 1997 and divorced in 2000. Ah yeah.
The most recent "crazy" is probably with that climber girl I met in 2009. She had huge windows facing the street and a sofa just in front of the windows. Of course we fucked on that sofa. Some teens were hanging out in the street, no idea if they noticed, she didn't seem to care.
All in all pretty tame.
I once masturbated on the Autobahn though. In a VW Corrado nonetheless. Anyone with a regular height car passing could have seen me rub one out.