I test in restaurants all the time, but I keep my monitor on my lap, and sometimes I slightly adjust my body so that it blocks my lap from the rest of the restaurant. I do this because I know that some people just cannot handle the sight of blood, and this is especially true if they are trying to eat something. In a private home, I test on my lap also, usually before the dishes start to get passed around. No one notices. I consider this just good manners.
For my own privacy’s sake, I would go to the restroom and inject there. However, since I now have the OmniPod, I can take my insulin by just working my PDM. Most people just think I am doing something on a rather “fat” phone. I love that I can easily take my insulin anywhere (car, park bench, beach, restaurant, etc.) with the pump.
I would encourage you to look into a pump if you are financially able to do so. They are life-changers and generally give a person better control than MDI! I did not want a tubed pump, so I chose the OmniPod. It has worked well for me.
I am blessed with a family that understands my need to test and to take my insulin before a meal, but if your in-laws have phobias about blood or needles, I would try to be polite and to accommodate their wishes. That is not being ashamed of your condition; it is just being considerate of others… even if you do not feel they are being considerate of you.
And as for the food, welcome to the battleground. In the end, I figure that life is choices, and I choose to eat only what I want to eat. You know what works for you and is healthy for you, so eat just that. If that means taking just a tablespoonful – or not – of the mashed potatoes, so be it. I agree with the conversation idea. If you keep up good table conversation, no one will notice or care what you do or do not eat.