How do you deal with relieving yourself?

When I go out for a paddle, I usually go for several hours. During this
time, I can get out on the shore, and do what I need to do.

I have a horizontal relief zipper on my OS Systems Breathable Dry
Suit.
Michigan winter paddling temperatures are tooo cold to completely
unzip.
Since the winter is often "drier" than the summer, I drink lots of
water.