As honkie said, proviron binds more advidly to the aromatase enzyme then other steroid homones which aromatize, yet itself cannot convert to estrogen, therefore it ties up the aromatase enzyme, reducing the amount of converted estrogen. On a cycle such as this proviron will do just fine. Proviron also binds more advidly to shbg, freeing up more of the other hormones to bind at the AR, and additionally proviron is methylated DHT, which, will support your libido, while on compounds such as EQ and dbol that eventually will cause a decrease in libido.
Proviron will be particularly usefull in the taper, as the drug can actually be increased, as the EQ tapers down, prolonging the effectiveness of the EQ, due to the shbg, and will support the libido. Proviron can then be tapered off once the Eq has sufficiently cleared the body.