A boar which slips during an early mounting attempt may become very shy about doing it again. If possible, collect a previously trained boar before initiating a training session for a new boar. Adjust the dummy such that it is equal to or slightly lower than the boar which is being trained. Make certain that the dummy is sturdy and anchored to the floor or wall. Others may want to explore the pen area and dummy and they may require several sessions.
Some boars require coaxing.
Straddle the dummy and continue the coaxing process. Try pouring semen from a previous collection on the dummy. Keep the boar focused on the dummy. If needed, place winged gates, hinged on the wall at the front of the dummy.