Need help editing Wordpress CSS code - my sub menu disappears on hover

Hope you can help - im extremely new and not clued up on code/editing css so hoping someone can spell it out for me. I have the problem whereby I can't keep my sub menu visible. When I hover over the parent item 'Destinations' it appears, and then when I move down to select one of the sub menu items it disappears.

can someone please check for me?

www.thespindrifters.com - It is under the Destinations tab

thanks in advance