Well I suppose mine would be chocolate, but it's not very secret!  I'm not supposed to eat it

but I do occasionally have some, but I buy very small bars so I don't have too much 'cos, like

Captain, I can't not eat it if it's there!

A non-food-related one is wild swimming.  I love to swim in "secret" places, well not perhaps that

secret but places where one might not immediately think to swim in.  It makes me feel wonderful

and all exilerated.  I am always very careful though as everybody thinks I'm bonkers and doesn't

want to do it with me!