When I am tipping/ spending I can be anywhere, in pm, the lounge, or actively in the chat room but that doesn't really answer your question.
Pre-spending on a model I haven't met, I usually use the preview feature, then a lounge/ pm view to make take a live peek (lounge is anonymous view option, pm may be noticed). Depending on what I see I will try a spend from what I believe is the best location for what I want.
With friends I just visit (no popup) or pm. Messaging is common as most of my model friends say hello if they see me on. I try to reserve active room visits only for when I have tokens or am willing to spend. I chose pm/ lounge vote because this is the most common way I interact with models.