He actually tells Mrs. Robinson to back off, and due to weird circumstances they have to leave his place. In the shower, after having vanilla sex, without tied wrists, and trusting her to remove the lipstick, he admitted that her was in love with her. Things are going pretty well. The sex on Grace, the boat, was a very creamy vanilla. Well worded, very nice, (I wouldn't have minded being out of her shoes) but didn't seem to take long. One would think that on a boat full of rope, she would have been tied somehow, but she wasn't. The vanilla sex they have, while I am glad they are having it, never seems to last long. Much kissing, long drawn out undressing, a bit of foreplay with breasts, the famous foil packet, and wham bam, lets get it on and over. Maybe it's all due to the written composition.
Things are not darker sex-wise, unless the darker story plot is what the author is referring to.