Quick Definition: When a couple publicly displays their affection, with gestures such as hand holding, hugging, or kissing.
Public displays of affection are pretty much exactly what they sound like—any physical display of affection between two people in a public area. PDAs are typically seen more in LTRs, but can also be used during the initial phase of a pickup to establish rapport.
There is some controversy within the community about whether PDAs help or hinder your game. On the one hand, PDAs help to establish your claim on a woman, so to speak, and communicate to others that you are in a relationship. You can establish dominance by publicly spanking a woman on the ass or going in for a quick kiss.
PDAs can also build rapport and establish a sense of closeness with a woman you just met, especially in the context of role playing.
On the other hand, PDAs can come across as beta, and even needy if done in the wrong way. Too many PDAs early on in a relationship or during a pickup can come across as too clingy and kill attraction.
PDAs can also send relationship signals to a girl, which is fine if you’re looking for a girlfriend, but not so good if you’re just looking for a casual fling. Typically, women appreciate discretion in casual relationships, so PDAs are usually not appropriate.
The appropriateness of PDAs often comes down to the level of interest the woman has in you. In general, showing more interest or affection than the woman is a bad thing and kills affection, because you end up chasing her and looking for her approval. If on the other hand, a girl is madly in love with you and wants to display her affection, a PDA can be an appropriate thing to do.