Actually I always thought it was a sin because it shows lack of self control which is a fruit of the Holy Spirit.
Galatians 5:22 By contrast, the fruit of the Spirit is love, joy, peace, patience, kindness, generosity, faithfulness, 23 gentleness, and self-control. There is no law against such things.
CCC 1832 The fruits of the Spirit are perfections that the Holy Spirit forms in us as the first fruits of eternal glory. The tradition of the Church lists twelve of them: "charity, joy, peace, patience, kindness, goodness, generosity, gentleness, faithfulness, modesty, self-control, chastity."112
So if we aren’t practicing self control I believe it’s a sin. And a common one…

But correct me if someone knows better than I…