This encounter is not unique. There are anecdotes in South America of raping dolphins in the Amazon river. Not only that there are trip reports from people one hallucinogens meeting dolphin like beings and having astral sexual encounters with them. Remember NASA had an experiment in the sixties about trying to teach dolphins language and it ended with researchers boning them. There was also LSD involved in that study.

What is the link between drugs, sex, and dolphins.