Shift the foreskin of your cock upward so there’s a good amount of it above your knob end, almost like the neck of a balloon. Either with lube or pre-cum, put one finger into the mass of foreskin and wind it round and round the bell.
Can be done solo or by someone else for you. Takes ages. A release of watery cum or piss helps boost the liquid around your knob end now and again. As your finger winds round and round you’ll feel one particular part of your glans or bell giving you immense pleasure. Find it Moist. Nick