Is there a way to determine "who" called "me" in a method? Or would doing this just be bad form?

I have a method in an object that creates another object FOR the sender. Rather than pass a parameter, it seemed like it would be nice to just "know" who was asking for the component.

For example, rather than

MyObject>>doSomething
     WidgetBuilderSubclass buildComponentForObject: self anObject.

it would be nice to just

MyObject>>doSomething
     WidgetBuilderSubclass buildComponent

and have

WidgetBuilderSubclass>>buildComponent
     | obj widget |
     obj := self thisMessageSender anObject.
     ...
     ^widget

I am probably asking a question that shows just how much I don't understand "the Smalltalk way!"

Thanks,

Rob