We put NO paper in ours. A little inconvenient, but sure does eliminate some problems. I know there will be some here that will disagree with this method, but it works for us & not that difficult to do. Good luck on a yucky clean-up.
We tend to put toilet paper used from urination in a trash can next to the toilet, but we flush down that used for BM's. Seems to have worked well so far. We use RV toilet paper though.
Try filling the tank about 1/4 full (or a bit less)of water before BM, then flush with plenty of water. I know it fills the black tank a bit quicker, however, it sure beats poking around in the toilet down tube with a stick!
Days camping (2015)----88 days
Days camping (2016) ---110 days
2016 Wildcat MAXX 28RKX (33' TT), 2007 13' Scamp
2015 Ram Laramie Hemi
30 years RV'ing
12 different RV's
X2 on what Turbs said, sounds like you aren't using enough water with each flush and now you have the "Cone of Death". I guess the toilet paper is better than the corn cobs we used when I was growing up.
2014 Palomino Puma 25RS
2011 F-150 Super Crew XLT
Days camped in 2014 - 23
Camped 2015 - 47
Camped 2016 - 51 done - 6 more planned so far