More than for fun I get the feeling that if I eat my blotter and swallow it then the comeup can feel a bit heavier physically than when I take it sublingually. I guess the sublingual route resembles a parenteral route more which may even matter for the generally physically light LSD. Maybe it pushes a few buttons on the way from the stomach to the brain and the gut reacts to it... but I don't know, this might only seem like it to me by coincidence. Or perhaps it's the paper and ink that I feel when I eat it, doesn't sit completely right with me but again it could be placebo. I always have a tough time understanding if sensations throughout the body are caused by action in the brain (the proprioception and general body 'feeling' parts) or if the drugs act locally and this is felt by nerve signals going to the brain. I guess both happen, hence my confusion I guess...
Could be that the majority is absorbed in the first 5 minutes but another 5 minutes does help with some significance. After that a lot of people including myself just try to catch the last traces by letting the paper turn to pulp and 'washing' it out in the mouth (soak, strain, repeat?), mostly 'just to be sure'. What I'd find an interesting interpretation of this thread's question is how much is lost on average if you spit out the blotter after 10 minutes instead of swallowing (again 'to be sure').
Also, I wonder whether it's the weird tasting impurities or the ink that can sometimes make me feel slightly ill or physically intoxicated in a typical way. But only slightly. I never had blank paper (WoW / white on white) before but it's in my possession now. Perhaps it will help me answer this question.