The chemicals you are speaking of are mostly secreted when our skin brushes against the skin of another. The most powerful release occurs when we kiss or rub our palms with an open hand over large areas of our partner. This is why slow, long strokes are so prized during erotic massage.
I definitely can attest to the fact that after sex where we are stroking each other we do feel a sense of closeness and bonding as well as slight euphoria and peacefulness. We tend to utilize these types of lovemaking sessions after we have either had a major stressor in our lives or we've fought over something. It's a way of mending the fences and bringing closure.
Even if you are normally very close you might notice you feel relaxed, giddy, or just quiet inside after lovemaking. The effects of the hormones/chemicals are sometimes very subtle.
If you stand behind and between your partner's legs while he/she is laying on his/her stomach and you lightly or even firmly run your palms up over his/her legs from ankle to upper thigh (you can use some light oil to help with friction) in long smooth strokes you can judge the degree of response from your body after about 10 minutes. You should begin to feel relaxed, sleepy, become turned on, want to talk, and/or drift peacefully. It all depends on how you respond to your own body and on your partner's response. This is an amazing way to reconnect without causing the fatigue that a deeper massage type rub down might cause for both parties. less