when you pay someone (i.e. a hooker) to give you a blowjob with a condom on
Hooker: wat would you like tonight?
Jimbo: i'll have a glumkin
When one recieves fellatio from a hooker whilst using a condom.
When your best friend gets a little too smashed and orders a blowjob from a hooker but decides to be safe and uses a condom. That is a glumkin.