Several weeks ago Cathy and I planned a weekend getaway to northwest Arkansas, lunch with SJ and Laura in Bentonville and a long relaxing weekend at Gaston's. The night before I installed the pod and topped off the fuel tanks in the Super Cub. We arrived at the airport early, pushed the airplane out of the hangar. As I opened the pod and the smell of fiberglass hit me and Cathy mentioned smelling fuel. I told her it was probably the fiberglass she was smelling since her smeller has been messed up since COVID. We loaded up and departed with a really nice tailwind, 140 mph plus. A while into the flight I was bored and I did a hard wing waggle to make sure Cathy was awake. We both smelled fuel, I said I must have sloshed some out during the maneuver but made a note in my head to check it when we landed. Our first stop weather was not as forecast so we landed on down the road a bit. They had no fuel but we were good because of the tailwind. I planned to check the caps and got side tracked helping Cathy in and didn't do it. Most of you know where this is going but of course I just kept looking at the fuel totalizer and out the window, totally oblivious. I was getting close to the Northwest Arkansas NTL airspace and wanted to go direct so I called the tower to request permission. They told me to call Razorback. When I dialed up Razorback they were busy and I was almost in the airspace so I opted to go under and around. Shortly there after over some beautiful forest the engine started sputtering. I banked left towards a clearing and looked at the left site gauge and it was empty, looked at the right and it showed a little. Leveled wings and the engine sputtered again. I thought, I got no time to jack around. I had two hay fields on the hill tops. One was past a tree line and I didn't feel like I could make it and the other was directly under me requiring a tight turn. No other options I made the turn while putting it in a hard slip and pulling in all of the P-STOL flaps. Just before we touched down, the ground adjustable Sensenich prop stopped, looking at the tree line ahead Cathy said we aren't gonna make it to which I replied "Bullshit". We touched, I dumped flaps and got on the brakes and we got stopped with some room to spare. I told her I guess that month of practicing for the preceding weekend's STOL contest paid off. My heart racing I jumped out and up on the tire and sure as **** I had left one of my gas caps off. I called SJ and told him what I had done, my heart still racing. I sent him a pin drop of our location and he said it would be a while cause it take a while to drive there. I told him he could land here easily to which he asked if I had raised a ruckus. Nope, no one knows we are here but us. He loaded up 5 gallons of gas and flew out and saved my butt. In the meantime I called a friend at home who went down to my hangar and found my gas cap right where I had loaded. Bad thing was I had done the same thing leaving the STOL contest at Gainesville the Sunday before. Needless to say my gas caps are getting chains and I have got to be more aware. A few miles sooner or later and it could have ended badly. Gotta thank SJ for coming to our rescue and Cathy for getting back in the plane with my dumb ass.