I get more pleasure from playing with another cock than I do from playing with my own. Partly it is the novelty, partly the pleasure it gives and partly to see the difference in his cock to mine and in the way it reacts. Finally to actually bring another male to orgasm is a great pleasure.
At my age and without any physical stimulation - never. Can get it up to a semi-hard level from soft when masturbating in about 2-4 mins depending what else is happening. On awakening in the morning I never have more than a semi at best. Usually only fully erect at orgasm.
Before the south Pacific islands were colonised, there was a completely natural system of sexual activity and introduction to it. Obviously, social and environmental circumstances were very different then.
For anyone who is interested in this history see any of the following publications (books).
Michael Moran. Beyond the Coral Sea; Travels in the old Empires of the South-West Pacific. London, Harper Collins
Bronislaw Malinowski. Crime and Custom in Savage Society (Anthropology)
Bronislaw Malinowski. Human nature, culture and freedom (A revaluation of our civilization)
Bronislaw Malinowski. Sex and Repression in Savage Society (Routledge Classics)
Bronislaw Malinowski. Argonauts of the Western Pacific (Illustrated)
The last time I was at the swimming pool; round about 1990. All the males who were changing were naked or getting dressed. I was standing at the dressing bench and there was a young guy sitting next to me. He had a towel over his thighs, but from where I was standing I could see his cock with a horizontal erection. He was getting an eyeful of all around him and of course of me as I dried myself with my towel. I gave my cock and balls some extra drying time to add to his pleasure. It would have been good to have met up with him later but the circumstances didn't allow any meaningful contact. He had a nice cock; probably about 17 cm as I saw it. It would have nice to have had the chance for a play with it.
I was invited to sexual activity with other boys who also did some voyeuring with older but wasn't drawn to it at age 9/10. I was introduced to cock play by older at 11 but still didn't take it up.
At about 13, after a late puberty, I did get involved with my friends from the boy scouts and we used to go camping in couples for the week end and have a good bit of exploring play. Then came the girls and later marriage.
It wasn't until I was very much older and the internet came along that I found a renewed interest in the prospect of playing with other males. Never had any inclination to engage in anal sex; or sucking as an active participant due to the health issues.
So, what that tells you in answer to your question, I don't know. Perhaps we are all different and find our way according to circumstances and what we fancy.
Can't really remember but I had a late puberty so it would be around 13. I remember that the favourite question I was asked by other boys was: have you got any hair around it yet? If the answer was, 'yes' then you would by invited to show them. The next thing they asked was can I play with it.
Of course all they really wanted was to wank me off.
When I was a boy my best friend was about a year younger than I was and he had a small cut cock; probably about 2 ins erect. His was quite sensitive and as I was uncut, I wasn't used to playing with a cut cock and in those days and in my circle, oral hadn't been invented! That was a pity because I could have given him a gentler time.
Even so, when the right opportunity presents itself there is something unique in mutual masturbation over solo. Each male has to find a way to stimulate his buddy so that he ejaculates and that may be simple or difficult; either way it is an exciting adventure.