What are the 5 cords of sensual pleasures?

The five kāmaguṇa are:

1. color
2. sound
3. smell
4. flavor
5. phoṭṭhabba (=temperature, matter, and vayo).

They tie the kāma-person to live in kāma-bhava.
kāma means "living in kāma loka"; and guṇa means "a binder".
So, the five kāmaguṇa are things that kāma-taṇha (addicting to drug), and bhava-taṇha (addicting to becoming, born to be, future birth).
See the first part of the mahadukkhakkhandhasutta for more information:

Now what, monks, is the allure of sensuality? These five strings of sensuality. Which five? Forms cognizable via the eye — agreeable, pleasing, charming, endearing, fostering desire, enticing. Sounds cognizable via the ear... Aromas cognizable via the nose... Flavors cognizable via the tongue... Tactile sensations cognizable via the body — agreeable, pleasing, charming, endearing, fostering desire, enticing. Now whatever pleasure or joy arises in dependence on these five strands of sensuality, that is the allure of sensuality.