Forearm grease

[Julian]

(noun)
Phenomenon that occurs when wearing a long-sleeved shirt, jacket, sweater, etc. while carrying out a messy task with the hands (such as painting, eating tacos, sorting garbage, moving dusty furniture, changing a diaper, [unclogging] a toilet, or having sex).
The [sleeves] are rolled up in order to aid in providing more freedom and mobility with the hands, however, those [gotdamn] sleeves keep falling down and refuse to stay rolled up, resulting in them getting in the way and being dirtied in the process.
Usually and inexplicably happens with a piece of clothing that the owner particularly likes.