Dependence of steric hinderance on enol content

The following is extract from my book-

To illustrate this, let us consider the enol contents of acetyacetone and $\alpha$ - methylacetylacetone. Although both the enols are stabilized by H bonding the enol form of $\alpha$ - methylacetylacetone is destabilized to some extend by steric repulsion due to the presence of $\alpha$ - methyl group.

What kind of H bonding (sorry I know i am being stupid, the figure in my book showed a bond connecting H and oxygen and dotted line connecting another oxygen and the previous hydrogen. How can hydrogen form two bonds?) is being talked about and what is steric repulsion? How does the steric repulsion destabilize the enol form?