My first anal orgasm?

A few hours ago I went to a friends house for what I thought would be our usual get together (mostly anal sex) While he was fucking me for a longer time than it usually takes him to get off, I started feeling really, REALLY good, better than you would expect even during good sex. I could feel his cock rubbing over my prostate, not just the sensation of getting fucked but I could actually feel his cock rubbing across my prostate and it was glorious! Next thing I'm having the hardest and longest orgasm of my life, I didn't shoot cum during this but leaked out tons of precum (normally I hardly precum at all) This orgasm lasted i guess 3 mins (yes 3 mins!) and didn't stop until my friend came and stopped thrusting.

What was that and can I have that again? Obviously this came from a lot of prostate stimulation, but has anyone else experienced this kind of thing? It felt like I was cumming for hours and was the best orgasm of my life. No cum though, just precum and the longest, hardest orgasm ive ever had :) Was this the so called "sissygasm" or "anal orgasm"?