"Bangla panu golpo" refers to adult/erotic stories in Bengali, often shared or searched for in PDF format. The specific reference to "free 26 — solid story"
: In many South Asian cultures, erotic literature (often colloquially referred to as "panu golpo" in Bengali) serves as a clandestine form of entertainment and sexual expression within a relatively conservative society.
The “26” you saw in search queries usually refers to the total number of stories in a particular anthology (most often “Pāṇur Bāri”).