Marine Sanitation Systems - Duck Bill Valves and Vent Filters

Do they make a fan to ventilate the air in the head? Like one in a house?

Tired, they generally use the same 12/24v fans that they use to ventilate the engine room and galley. They are called blowers. Quite noisy but effective. You can also buy solar fans. Just ask at your local chandlery, they should know.

I never put toilet paper of any kind down my toilet. They go in a plastic bag and then in the garbage.