The only citation of Psyllium 'sticking' that I could find comes from, guess who, Citrucel.
Most sites are more in tune with:
Don’t waste money on Metamucil or other highly promoted products. The pure generic stuff sells for 5-8 clams for 12 oz. and contains no chemicals. Psyllium is virtually inert. It adds natural bulk to your diet. In addition to adding bulk fiber to your system, it acts as a gentle sandpaper on the walls of your colon. This gradually dislodges the waste material which has been collecting for a long time.
I love Psyllium and won't get carried away with someone finding need to yap about everything on the market. 100% psyllium is 100% fiber and I've never seen anecdotal or studies saying it could 'stick'!