fic ideas I have no clue how to write

I want a fic where Duke takes Nathan diving. (Like, actually diving, to the sea floor, not as a metaphor for anything smutty.)

I know nothing about this subject. Would anyone on my flist happen to know it, and be able to give general links/advice, as well as advise me what kinds of problems someone who can't feel anything might have trying to undertake this activity? (Perhaps it would only be possible after the Troubles were gone.)

If someone knows the subject and Haven both and wants to write the fic, by all means feel free to adopt this plotbunny from me.

If not, I haven't written a short, happy bunny in awhile, so I may attempt research.