Baptism is a Christian sacrament. Baptism is usually given to babies and may be called christening. In the case of Adult Baptism - it happens when an adult elects to be a Christian - and is used a a symbol of the washing away of that persons sins. Baptism of the Holy Spirit is the receiving of the Holy Spirit - this happened in the Upper Room at the feast of Pentecost as told in the Acts of the Apostles. Anyone may seek baptism of the Holy Spirit by way of prayer and fasting, or by attending a Pentecostalist or Charismatic Church.