Throw a committed strike at another aikidoka and a number of things happen. You have offered your physical energy, your ki, to this other person. They respond, in one of myriad different ways, and for a moment they harmonize energies with you, and then separate as the technique is completed. Then it is your turn to receive the attack.
There is physical touch involved. There is a element of great trust. The lurking potential for an injury is always there. Doing aikido, class after class for months and years, has changed me in ways I would not have expected. It seems to change everyone who practices. For the local group that you work out with regularly, it builds bonds of friendship and shared experience.
Sensei Suenaka gave a talk last week about the Aikido community as family. Specifically, the word he used was the Hawaiian word ohana. The word means more than "family" does in English. It means the extended family, to include family we build by our intentions and actions. Family binds us by ties of love and trust and obligation. This, then, is a picture of my family.