My friend Allen and were mutual masturbators who jacked together 2 or 3 times a week after school beginning when we were 12. On the weekends we ad all day for jacking, so we jacked until our dicks didn't produce sperm.
Alan and I were usually left to ourselves on Saturdays when our families were away playing golf, bridge or doing other things, so we had our houses to ourselves. We usually had 2 or 3 mutual jacking sessions, but on Saturdays we could jack as much as our peckers could take. I could produce sperm for as many as 5 orgasms, but the 6th and later ones were dry. Alan did about as well. We called this excessive jacking 'milking our cows.' When we awoke on Sunday mornings, our dicks were so sore we could hardly touch them. Mine had a doughnut back of the head, and Alan's looked worse, being uncut.