I was circumsized as a baby so I don't have a foreskin but I have been doing restoration and have what is called a faux foreskin.
What I do is grab the extra skin under the frenulum and pinching it I pull it forward way below the tip of my dick and then back uncovering the glans. back and forth I go... sometimes it gets caught behind the crown of the glans but I free it and keep going back and forth. I just pinch and move it back and forth. and pretty soon I get a good spurt. I don't exert any direct contact on the glans with my fingers and I don't make the classic circle between index and thumb.
All these years and I just discovered this.