Hey, i'm not sure if anyone has posted this before, but I was looking at this, and figured it'd be great to carry weed with.
I take no credit for this, i am just posting the link. You can carry it with you at all times and no one would be the wiser, it's somewhat normal to carry a marker around.
How to make a simple safe to hide your money in your car
Here is another link on the same site on how to make a water bong, not sure how useful or effective it is tho.
how to make a water bong