Here is a trick......
With your toes covertly make a small trench at the end of your towel..... after you have it about 3" or 4" deep and 12" or more long just sneak your bare ass to the edge and pee into the little trench.....after you finish bury it again with sand.

It is best if you do this in the tide zone so that the pee'd on sand gets cleansed soon and thusly no stink will occur.

From a total environmental stand point it is best to pee in the water...... and as you can guess poop only goes where it belongs and that is not on the beach or in the surf.

(I know you know that last point Olivia, just saying it for others.)

There is "the spot" up the hill a bit, towards the north end of Baker, where people go to pee.

Or one *could* don clothes and walk to the south end, where the bathrooms are....