Let it flow i say... then wash your shame off, and out of the cockpit, when you next stop.
There's not much you can do really, especially if you're a female.
If people are looking for solutions, google female p-valve, as there was work in progress when i finished up diving for a female solution to connecting themselves to a pee valve in a dry suit. Essentially the same for a kayak, but you'd just have a pee bag in the 'pit or drape the hose over the side.
Gotta be careful with pee valves and condom catheters wether you're male or female:
1. Urinary tract infection is possible with back flow and the like (so running the line up and over the cockpit rim might be an issue actually)
2. Your fiance will come home and find you in the faetel position on the bedroom floor because you've decided to try a condom catheter on to see how they fit and connect to the valve of your drysuit, forgetting that they are held in place with a mild adhesive. Unless you've trimmed the area in question, certain hair will be trapped by the adhesive making removal of the condom catheter a rather tear-jerking experience - from pain or from laughter depending on if you're putting one on or you're the fiance that found their partner on the floor in agony, writhing around trying to wrestle the condom catheter off his johnson without giving himself a brazilian wax.
Food for thought people... food - for - thought.