I was very lucky once when renting a room in a larger house. The room came with a king sized bed but weirdly the landlord used two single mattresses put together on the bed rather than one large king sized mattress.
Between the two mattresses was a perfect space to wedge my fleshlight in and have hands free fun.
I actually used this technique to help me with partner sex later. When I finally lost my virginity I found it difficult to climax. Talking about it with male friends this really is not as rare as you might think.
Orgasming this way, not using my hands, through thrusting and being is a position very close to missionary, really helped me to relax and get used to cumming in this way with a partner.