Cialis is intended to be metabolized and processed through the digestive/endocrine system and carried to the appropriate cells by the blood system. I doubt Cialis in DMSO and absorbed directly through the skin without being process through the endocrine system will have any of the desired effects you are anticipating.
Also DMSO will allow the Cialis to be carried through the skin to the interior tissues of the penis in its raw form, which carries a risk of harming the internal tissues. Accordingly, I would recommend against it.