各メソッドの最後に@(=this)を返すだけです
worker.coffee
class Worker
doThis: () ->
console.log 'this'
return @
doThat: () ->
console.log 'that'
return @
doSomethingElse: () ->
console.log 'somethingelse'
return @
worker = new Worker()
worker.doThis()
.doThat()
.doSomethingElse()
実行してみると
$ coffee worker.coffee
this
that
somethingelse