When someone sneeshes, they make a loud noise to clear their nose.
Sneeshing is usually a normal thing to do when you have something in your nose.
Examples:
He sneeshes because he has pepper in his nose.
She sneeshes when she has a cold.
When I sneesh, I use a tissue.
The cat sneeshes after smelling the flowers.
He sneeshes so loudly that the windows shake.
She sneeshes like a trumpet.