First question: very yes!
Diet affects the taste of semen a lot. If you have a diet heavy in red meats and fried foods, your semen is going to taste bitter and gross. A healthy diet of fruits and vegetables and lighter meats will make it taste better. Eating lot of fruit can even make it taste sweet.

Secondly, it depends on exactly what you mean by "in porn." Do you mean coming in a lot of heavy spurts? Do you mean flying across the room?

There is no need to ejaculate like that. However you cum is just fine.

Yes the food you eat can effect the taste of your semen. Can't help ya with the porn thing though.

They're right on the first question. The second one I've heard varying things about. Supposedly, with a special diet and certain supplements (like larger amounts of zinc), this is possible to achieve.

first question, yes it does. so eat well . . .
second question, you can. just hold off you penis when you feel you'll ejaculate for about 3 to 5 seconds, and let go of it after. ENJOY!