historically known to have ran a farm in Utica, NY and owned the largest cow recorded in history (called charles) and was the top in the milk industry in the olden times
shimaidon is genre in which someone is able to get their way with two sisters. Futago means literally twins, Shimadidon futago it's Shimaidon with exclusive twins
Step-sister is bland, the real thing is shimaidon Futago. Two piece of meat from the cow
Basically, this is said as an entry-level phrase to someone you have a favorable impression with, or if you are a very 'traditional' person. Another situation you would use this, is if you were being convinced to accept someone's hospitality. I am unfamiliar with the direct transliteration, but if you wash the grammar properly it comes out to be 'Please treat me kindly' or 'Please take care of me' or 'I am in your care, kindly' something to that effect. As you can see, this phrase is a trade of trust, where you 'ask' for trust, and 'give' trust by 'placing' yourself in someone's care.
Source? My frequent visits to Japan, and familiarity with its culture.
- Here, an underclassman at school or work who might have previously met this person they refer to as 'senpai' (or senior, upperclassman) Implores them to continue their goodwill now, and in the future. The meeting may be in front of the senior's friends, so the person wants to be respectful so their senior doesn't lose face.