A classic side by side position, for anal sex. Usually done on a flat surface, such as a bed, both parties are laying in a prone position, during the penetration, and subsequent thrusting.
Infidelity is basically the violation of agreed upon rules, or behavior among committed persons.
Not necessarily married couples, but is about a break of trust, either in an emotional sense, or more commonly noted, a sexual sense between two parties, involved in a supposed monogamous relationship.
Supposed to be 'the' position, for first timers, or for those who like it easy and intimate.
Both parties lay prone, but on their sides.
The Receiver (the one being penetrated) usually uses their one hand (one on the bottom) to prop up their head.
The arm is spread forward, in line with their head, the forearm up and holding the head.
The body is slightly askew, with the lower portion more towards the corner of the flat surface
The leg, laying on the flat surface, is usually arched backwards, towards the Giver.
The top leg is then spread forward, also slightly bent at the knee.
The Giver (the one doing the penetrating) lays alongside the Receiver.
They have their forearm resting flat, aimed towards the Receiver, not in line with their own head.
This allows them to use the arm to steady themselves, but not actually prop up their head, Further, it helps to align their upper body off the flat surface.
The Giver's lower body, molds into the angles of the Receiver, so that he/she can penetrate easier.
Usually the Giver's upper leg (one off the flat surface) rests either on or besides the backwards spread leg of the Receiver.
Hooking their leg over it, can further help to open up the rear end, for better penetration, as well as to provide a form of control over the thrusting power.
Practice (Associated Acts):
An easy position, to turn into other sex positions, by one rolling over on top of the other.
The Receiver can roll backwards, so they are on top, or vice versa.
This position offers both parties an opportunity for more intimacy.
The Receiver can easily masturbate themselves, while being pounded, or the Giver can reach over to fondle, and stroke as well.
Also it is possible, with a bit of contortion, for the two to engage in kissing.
The Giver can easily nibble and fondle the Receiver, and help in increasing the pleasure, from his/her touch.