Does slime come from the upper back end of a slug?

Does slime come from the upper back end of a slug?

Observation - Does slime come from the upper back end of a slug? - UK and Ireland. Description: Slug. Black. Shiny. About three inches long. Slime seems to be coming out from the TOP side of its rear end. Is this the usual way a slug extrudes slime or is something else happening?

Slug. Black. Shiny. About three inches long. Slime seems to be coming out from the TOP side of its rear end. Is this the usual way a slug extrudes slime or is something else happening?