"Milf" stands for "Mother I'd Like to Fuck", which refers to a hot, older woman who may be a mother or just an experienced woman. In this context, "Towm" is likely a typo and should be "town". So, the phrase "milf-towm" means a sexy, experienced woman from a small town or living in a rural area. This tag can be used to describe a porn video featuring a MILF from a town or rural setting.