Such waltzing was not easy.
We romped until the pans
Slid from the kitchen shelf;
My mother's countenance
Could not unfrown itself.
The hand that held my wrist
Was battered on one knuckle;
At every step you missed
My right ear scraped a buckle.
You beat time on my head
With a palm caked hard by dirt,
Then waltzed me off to bed
Still clinging to your shirt.
Line represents the attachment and love the child has for their father.  The child doesn’t simply hold onto their father, but “clings”.  This may be indicative to either how much the child looks up to their father and wants to spend time with him, or how the child misses their father when he is away, presumably doing heavy work somewhere because of the “palm caked hard by dirt”. 
 
 Reading this poem from the view that the father abused his son, this line could be interpreted as the son’s blood from his beating still remaining on his father’s shirt. Another meaning could be that the son himself was literally hanging onto his father’s shirt, begging him to stop. You could even say that the child was determined to hang onto and care for his father despite the abuse because he knows nothing else.
My Papas Waltz