I just chop up a good big lump of fresh ginger into chunks and add boiled water, honey to taste and let it steep for a bit, worked wonders with those really nasty waves of nausea after waking up.
Then I found 2 ways to (in my case anyway) prevent it: firstly, dont bother forcing yourself to sleep uncomfortably for a couple of hours, just stay awake and through to thenext evening, but stop taking the meph in the afternoon. Eat something decent for dinner and get a good nights sleep.
Secondly, absorbtion of the mephedrone dissolved in water, thru the oral mucosa/sublingual by basically just sloshing it around in my mouth for a good 30 secs - 1minute, whatever you can handle.
Aswell as bringing it on faster than bombing, it (ALLEGEDLY) helps a lot of it skip first-pass metabolism in the liver, so it goes into your bloodstream unchanged, without having to go through your liver initially which is what creates the dodgy metabolites, and leaves them circulating in your system for longer during the experience and while you're coming down. (At least that's my understanding).
I've never had the sweaty fucked up sleep, or bouts of nauseua since applying that aproach.....