I discovered a case report of a similarly afflicted fellow, although not in a peer-reviewed medical journal. Allow me to quote from the case:
"Although defecation process is known to be controlled voluntarily by means of anal sphincters, the intentional relaxation of these sphincters per se did not produce any visible effect in the individual under study. Only when the subject was simultaneously presented with sufficient amount of printed text of any kind, written in Russian or English, the defecation process started. The extinguishing of the trigger stimulus from the subject's visual field resulted in almost immediate suppression of the defecation. We found no effect of text relevance, quality or informational content on its stimulation efficiency."
Perhaps book browsing causes your “Biblio BMs.” The fix? Try ordering your books online from either library or bookstore to choose your defecatory setting.