Roughly chop the chocolate coating. Heat milk and butter in a pot, remove from the heat and dissolve the chocolate coating while stirring. Then slowly stir in the coffee liqueur bit by bit. Pour the mixture into a bowl and refrigerate for about 3 hours. Halve the truffle mixture and first whip 1 half until creamy (just under 1 minute).
Place in a piping bag with a medium-sized star nozzle and squirt a tuff into each half. Mix the remaining truffle mixture until creamy and fill the remaining half shells with it. Put the men's chocolates in a cool place for at least 1 hour. Pack the pralines well and store them in a cool place. Dust with cocoa only before serving