[mcv]

Perhaps it's an idea to secure yourself with a safety line when you need to pee on a boat.

I've sailed a lot on small, open boats, and I tend to lean against the rigging. That gives me something to hold onto.

[Kon-Peki]

In boats large enough to have multiple people on them, there is going to be a head available (in the US it's part of a tax loophole), but people still pee off the side. If you do so the other people on the boat very much appreciate you using the leeward-most part of the boat, where rigging is not always available.

If you heave-to whenever someone needs to relieve themselves, you get a double bonus - a smoother motion in the water and rigging to hold on to.

[mcv]

I forgot at what course I used to do it. Possibly several, but yeah, always leeward of course. But even at regular beam reach[0], you can still stand between the sail and the shroud[0]. At broad reach[0] or running downwind[0], you can also use the fore stay[0].

[0] I have no idea what the English words for sailing terms are, so I'm googling all of this. Hopefully correctly.

[Kon-Peki]

You have the right words :)