Although Lesotho is completely landlocked by South Africa, it is very much its own country and so, when planning a trip to Lesotho, it is crucial that you treat it as such, and make sure you have all the necessary documentation that you will need to enter and exit its borders.
Check out the following pdfs to make sure you have everything you need.
Important forms: medical, indemnity & letter of consent (also included in team pack)
Parental consent affidavit form (South Africa Home Affairs)
If you are not a South African citizen, please make sure to contact the Lesotho Embassy to make sure you will be granted entry into Lesotho with your type of passport and visa. Just because you have a visa to enter South Africa DOES NOT mean you will be granted entry into Lesotho.