First use and still using.
I was sitting at that end of the couch first. Had my feet up on the ottoman, had my coffee on the end table.
If I pick up my coffee to drink, I hope the intent to put the cup back down ought to be clear. Nobody gets to say I was done with the end table and take it away before I finish my sip.
If I get up and go to the kitchen for more coffee, I hope my intent to return to the couch and use the ottoman and end table again are clear, nobody gets to assume I am done and take over use of those things.
But sometimes I go to my desk, so I am done at the end of the couch. I am also still present and can be asked what my intentions are.
So nobody has any reason to assume availability of something they've observed others using, and really ought to ask if others are present.
I see some of my students behave differently in class. I don't have enough rulers, compasses, and protractors for everyone, so they must be shared. Male students will typically simply just grab whatever they want, then retain it on their desk (implying intent to continue use or even claiming exclusive use, ownership) instead of returning it. Female students will usually ask if another person is using a tool, either reaching for it partially or pointing at it, and then return it to a middle place, neutral ground, when finished.
Conclusion, using it now does not imply forever. Share. Communicate. Ask may I, and say thank you, and return conditions to a neutral state after. Don't hoard.