Pumping up DinghyDogs takes time with a foot pump and it isn't exactly easy. You might try this.
Press the yellow button in and turn clockwise to keep the valve open. It will be much faster and easier to pump up the tubes. When they're pumped up, remove the pump from the valve and QUICKLY shut the valve - turn counter clockwise so it pops up. You'll lose a little air but not much. Now you can finish the pumping the regular way but with much less overall effort.