You pull the skin back behind the head when the penis is erect. Put the condom on the end of the penis while the condom is still rolled up. Unroll a little of the condom on the head of the erect penis and squeeze the air out of the end of the condom and then unroll the condom down the shaft of the erect penis until you get to the base. If the condom does not unroll entirely that is OK. If you do this it should work fine.