Can’t imagine doing it without thinking of someone- if not using porn, 99% of the time will think of someone I actually know, maybe 1% of the time someone famous, etc.
Always my wife with someone else’s wife…
The Japanese have a word for this. It’s something like “ona-idoru” from “onanism” and “idol” (idoru in Japanese). (I say something like because I can’t get the word to come up in a search but I’ve seen it multiple times, maybe another Doper will know the exact word)
I don’t particularly. I usually just watch whatever’s on TV.
I can without one, but it takes a long time and it’s much more fun with a fantasy typically.
I’m sure you’re tired of hearing it, but I instantly thought of you when I read the thread title. 
I generally don’t have anything in mind. Sometimes I start with a fantasy but I tend to get distracted.
I don’t need an object, usually. In fact, hardly ever.
Not me. I don’t need to think about men in thick rubber Hazmat suits and SCBAs cleaning up toxic chemicals to get off. I don’t have to envision the reflection of the sun off the aluminized fire-proximity suits of men putting out an aircraft fire in order to attain orgasm. No siree.
Well, that’s one less thing for the dishwasher.
The Jet-Dry & KY were reacting badly anyways…
Gotta have living, breathing, skin-on-skin… my SO, and only my SO
I don’t think you understand the OP…
I used to think Masterbate meant to chew your food.
I don’t think that anymore.
Wow, you think of Autolycus when you rub one out? :o
Sometimes I get so caught up in the details of making the fantasy believable enough that I get frustrated and just go at it frantically with no particular train of thought. If I can see a fantasy through, it is usually a more satisfying experience.