In male Chilangos' psyche these two concepts constitute a full taxonomy of single women. On one hand, a woman is said to be apretada (ah-preh-TAH-duh, lit. tight) if she refuses to engage in sexual intercourse even with the one she loves or is interested in. It's an allusion to apretarse el calzón or holding her panties tight.
The opposite of apretada is ponedora (paw-neh-DOUGH-rah, lit. the one who puts): a sexually promiscuous woman. An alternative expression for ponedora is sí le pone. (ponerle means to engage in sexual intercourse.)
Both apretada and ponedora are ansolutely informal and even offensive.
Juan: ¿No que tu ex era bien apretada?
Carlos: Desde que cortamos se volvió bien ponedora. Chale!
Juan: I thought you said your ex was very conservative.
Carlos: She became very promiscuous after we broke up. Damn it!
Note: A man can be said to be apretado, but nobody refers to a man as ponedor (that's believed to be the default status of men).