Set the strength at 1.1 or 1.2. Put parentheses around the tag: '(4_arms)'.

Generates people with 4 arms. Should be able to handle 'facing viewer', 'from behind,' and 'side view' and does pretty well with 'reverse suspended congress'. Putting 2 different hand gesture tags in the prompt seems to help a bit too. It absolutely cannot do single handjobs, but apparently 'handjob gangbang' works, and honestly, why would you want anything else with 4 arms?