Stretching can be done extended and deepened with the help of a partner. This is not a new concept at all; pnf stretching has been done for years. Proprioceptive Neuromuscular Facilitation is what PNF stands for. Done safely, you can have someone at home help you with your stretching pushing you beyond the passive stretch. With natural reflexes it make is tough for us to stretch ourselves in certain ways. Using a wall or towel helps but having a partner increases the efficacy.
You must be clear about the partner moving slowly and be in full communication during each inch of movement ensuring that they understand they must stop or back off immediately if you say so or you can pull the muscle. All this is discussed clearly prior to beginning. Ensure they follow your instructions step by step so that you are ready.
Chest and Hamstring stretches are most popularly used for this type of stretching and ironically are the 2 stretches every human should do at least once per day partnered or not.
With the chest stretch you have the partner sit behind you and you put your arms out to your sides, level with shoulders and palms forward as they hold your palms and slowly, evenly bring the arms back and slightly downward until you indicate you are at a mild stretch point. You then can also lean forward into it a bit but let your partner know you are doing this so they remain stationary. After 20-60 seconds have the partner release about an inch off the stretch and you will pull against them for 6 seconds while they brace themselves and remain stationary. Once you are done pulling away, they should then pull the stretch deeper by an avg of 2 inches or so. Repeat this process for a total of 2-6 times. Release out of this very slowly having the partner ease your arms back once you are done your stretching.
You do this same process with the hamstring stretch which is done lying on your back with a leg in the air. Have them stand at your feet and in a lunge position so that your foot is on their shoulder by their ear and they can cup your knee with one or both hands. This allows you to push against them during that phase without them loosing balance. During the stretching process the other leg should be like limp dead fish. Maximum relaxed.
After a session of stretching like this you should make sure to take in a few liters of water to help flush the toxins you just released out of the muscle and into your system. Now you will have fresh blood brewing with oxygen filling the muscles and you may even feel this by getting slightly light-headed once you get up. This allows healing and lean muscle growth. You are also preventing injury and avoiding simple pains many suffer because of not stretching. All the best in your health and flexibility!