It is to be administered orally. It has no taste so the frog will not try and spit it out. If you have a feeding syringe you can use that. You buy just plain mineral oil. Stores will sell it with the laxatives and stomach reliefe medications.
Only give a dose every 3 to 4 days. The oil will soften the blockage and you will be able to feel the stool soften inside the frog. Continue soaks while using the mineral oil.