Even though St Pio was a priest, he received the Holy Eucharist on the tongue. Even though he had the wounds of Christ is his holy and venerable hands, he received the Holy Eucharist on the tongue.
Incidentally, our Holy Father Pope Benedict XVI is instructing everyone to receive Holy Communion on the tongue at all of his public Masses.This is something that our Holy Father is publicly embracing. As the chief shepherd of the entire Church and as the "chief liturgists of the liturgists" His Holiness is leading the Church with this example and pattern.
If you want to start receiving our Holy Lord on the tongue at Holy Communion, and don't know how, here are: Five Easy Tips on Receiving Holy Communion on the Tongue.