Unless you take an AI, preferably arimidex 0.25 ED you will hold quite a lot of water on testosterone. Alternatively you can use 10 mg of nolvadex ED or one of the over the counter AIs such as 6-OXO or ATD.
The reason you need to control estrogen while on a cycle of testosterone is because testosterone aromatises to estrogen contributing to high circulating levels of estrogen while on testosterone.
In any case ensure you have nolvadex on hand in case you develop initial signs of gynecomastia. Initial signs include tingling or itchiness around the nipples or a new lump behind the nipple.
It's wise to press, but not squeeze your nipples every day to check for a lump. If you squeeze your nipples you tend to bruise the tissue beneath the nipple and your nipples can tingle for days afterward.
The arimidex is the preferred option next to nolvadex throughout the cycle, but if you try one of the OTC AIs such as 6-OXO or ATD, you should report your results because while the manufacturers of OTC AIs claim their products are effective for the purposes of controlling estrogen while on cycle, nobody on this board to my knowledge has reported results confirming this.