Paul command to pray without ceasing implies that unceasing prayers is like breathing. But how can our prayers become our spiritual breathing?. The way to do this is to call on the Lord Jesus continually. This is the way to breath, so you should pray without breath
1Thessalonians. 5:16_18" 16 Rejoice always,. 17 pray without ceasing,. 18 In everything give thanks, For this is will of God  in Christ Jesus toward Us"