Dude, just bathe them ( the testes ) on some hot water, i.e, not hot enough to hurt of course, but hot enough to make it a bit unconfortable.
Heat = motility which is what you are looking for. Put them inside a water container, the whole thing for a few minutes b4 go time and you'll squirt like a mad man.
Also, take the above advice on loading water, increase water intake 3 fold, i recomend about 3 bottles of water a day, to everyone. People drink way too litle of it and don't even remember it is the most basic building block of life...litle old water. That's what we are made from along with some trace elements like calcium and such.
Yes, water intake does have direct influence on semen motility, if you are dehydrated in the very least the body will have less water in it's cells. Also, while dehydrated, you get less of plasma, the transparent "stuff" that carries your sperm cells. THAT is what makes more or less liquid.
Also, stress is a no-no...It dramatically reduces sperm count and quality. Relax, breath in, breath out, wax in, wax out lol whatever calms you down brotha.
Peace out dudes
Mike