YMPA

Originally entitled the Young Men's Reformed Cultists of the Ichor God Bel-Shamharoth Association but commonly called the Young Men's Pagan Association, this is Discworld's version of the Roundworld institution, the Young Men's Christian Association. Heavily parodied in song, the YMCA - and, by association, the YMPA - offers a room and food to those in need,

The YMCA is a world-wide, largely nonsectarian and apolitical social movement with a special emphasis on community development and young people. It uses a holistic approach to individual and social development encompassing spiritual, intellectual and physical methods.

Presumably Bel-Shamharoth (whose very name caused Rincewind's ears to try to crawl inside his head in horror) isn't quite so concerned with such community spirit...

The only towels that aren't fused to the rails (it's the appearance that matters, not the function) at Death's Domain are inscribed with YMRCIGBSA, so were presumably stolen by Albert from the premises of one of these hostels during one of his infrequent trips to reality.

Annotation

Founded in 1844, the YMCA, which began among evangelical Christians in London, was unusual because it crossed the rigid lines that separated the different churches and social classes of England, making the YMCA a pioneer of ecumenism. This openness was a trait that would eventually lead to the inclusion of women and children and a culture of acceptance of people of different faiths and backgrounds. Today, the degree to which religion is emphasized in programs varies between individual YMCA associations. Generally, YMCAs are open to all, regardless of faith, social class, age, or gender