Once it gets longer...the hair at the top of the bridge...is pulled up into the topknot. That's why you don't want to cut it...if it's cut the topknot looks very skimpy.
Petzlife makes a dog hair gel. You can find it online...or I will confess Reggie has had bed head styling products in his hair. LOL.
Here's a picture of a yorkie in coat...but you can see it's topknot very clearly. You can keep the beard and body shorter of course.
http://www.sharonsyorkiepuppies.com/...ie-384x398.jpg