We are identical twin brother athletes (world ranked tennis) and in every respect heterosexual although we mutually masturbate together as a natural sameness perhaps unique to identical twins. I have no idea about others but since earliest memory we have done everything together and the early discovery of masturbation was no exception. Physically we are indistinguishable in every respect, including primary and secondary male characteristics and survived the maternity ward with foreskins intact. We spend most of the year traveling playing golf as well as playing/teaching tennis, and have limited opportunity thus far for serious female relationships so our sexual activity has been largely limited to masturbation.
We live, eat, sleep together and as natural as those activities, we masturbate together as well. And of course that's what this contribution is all about-masturbation. I suppose two adult men naked on a sofa or together in bed mutually masturbating regularly and frequently should modify my declaration of heterosexuality-we do it very mutually sharing it right up to final ejaculations which are produced in drill-like precision and usually, in awesome velocity and volume. And the inspiration can be mixed-usually female but also male. So perhaps indentical twins are in practice bisexual to a degree-whatever! Of course male masturbation produces a material result-a load of sperm/semen, whatever, but a very liquid product and I/we believe that product hugely heightens the level of the experience. It seems a lot more than just coincidence that liquid product is actually solid protein and to the dedicated masturbator, more than just edible. That can have a decided 'twin' impact as well.