Don't try to suck the air out of the skies, use it softly, at first, place the mouthpiece about 1/4" in your mouth and lip it don't bite it, then make a few soft sucking motions like your kissing your wife, cup your hand over the bell a little this will icrease the voloume some, to make higher pitched sounds, tighten your grip with your lips, and increase the suction somewhat, try really quick spirts, you can also place your middle finger inside the bell some while you are using the call to help soften and lower the pitch. Do a google search on Scott Wilhem, he plays a wicked trumpet and he may have an instructional video or something that may help you. Just takes a lot of practice, using your diaphram instead of your belly muscles......
