Line a baking sheet with nonstick baking paper and place in the freezer.
Melt the chocolate in a heatproof bowl set over a pan of gently simmering water, then leave to cool slightly.
Cut each banana into 3 then insert a lolly stick into the end of each piece. Dip them, one at a time, into the melted chocolate to completely cover, using a spoon if necessary. Tap off the excess chocolate.
Sprinkle the lollies with the sugar strands or sprinkles, place on the baking sheet and return to the freezer for 3–4 minutes to set.