When I was 20 I slept with a 42 year old professor of mine. I can confirm that it was fucking out of this world. I still think about it, and even though she doesn't work at my alma mater anymore, I do hope our paths cross, because she was a freak.
Since no one ever likes to believe this story, I'll give some background.
I was in a summer research program, and she led it. I had never had her for any classes yet, so I wanted to make a good first impression. I showed up 15 minutes early, introduced myself, helped her finish setting up the room (it was summer, so we had full use of one room, so we had it set up as a full-time lab just for us).
What I didn't know was that she was having marital problems, and actually asked her husband for a separation (or so she says). This explains why she was so receptive to a fling.
So I tried really hard and stayed on top of the readings. What else would I do? It was summertime in the middle of bumfuck nowhere (my college was a rural college), and I just did what I was told.
I even solved some problems when we were low on diluent that wouldn't change our methodology too much.
So we went to a BBQ at another professor's house, and she was (unbeknownst to me at the time) hitting on me. Laughing at everything I said, rubbing my arm...the stuff that made me go "hmmm...." but stuff that nerdy me would shrug off.
Our little town did have one bar, and I had a fake ID. So the class went to the bar, and got hammered. She was there, chain smoking on the patio.
She finally found our group, we chatted, and she asked to go back to my car (I don't drink and drive, my buddy had my keys and he was sober). We got a six pack of Smirnof Ices, and went to town on them in the back seat.
We get back to my dorm, and she's hanging with us. A little weird (especially since at this point, she was happily married to the husband I met at the BBQ, or so I thought), but whatever. She wanted to go down and go for a walk by the lake.
She flat out told me she wanted to make love. I was pumped. We messed around, but for some reason, vowed to put it off until the end of the program.
We fucked on the day we did the final presentations. It was awesome. She slept in my dorm on my tiny fucking bed and woke me up twice with her mouth.
tl;dr - She was a Ph. and I gave her the D.