c# - Multiple particle emittion locations -

i following tutorial on particle systems in xna: http://rbwhitaker.wikidot.com/2d-particle-engine-1 , fine tutorial, can't find easy way have particles emit multiple locations properly. tried put

particleengine.emitterlocation = new vector2(mouse.getstate().x, mouse.getstate().y); ,

particleengine.update(); 

in loop every place want appear, speeds particles (since being "updated" multiple times per update). way fix this? thanks!

edit: clarify, want know how make particles emit multiple locations, not why updating multiple times per update