Your tail rotor creates thrust that pushes the helicopter left. You have to counter this with a little right cyclic, but not too much. This is perfectly normal.
I would strongly suggest getting a training gear or making one. Training gears saved my bacon on at least 20 occasions. Without a training gear, your helicopter very well could tip over and if the blades strike the ground, things will get messy.
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If you watch any video of a Trex hovering, you will notice that they are banked slightly to the right. This is the result of having to hold a little right-cyclic to counteract the tail thrust.
Probably not the best video, but since I am still a noob, you can see my delayed reaction during takeoff in this video of my Trex-250. Just jump to 1:50 in the video.
You will notice that the helicopter doesn't tip to the left because I am counteracting the tail with the right-cyclic. You will notice immediately after takeoff that the helicopter starts to slide to the left. I quickly counter this to hold it still in a hover, but this left-ward slide is an indication that I didn't give it enough right-cyclic while spooling up and taking off. You will also notice at about 2:17 as I am climbing that the helicopter is indeed banked to the right as I previously mentioned.
You will want to give a little more right cyclic than is needed to keep both skids on the ground. The key is to be very gentle in your inputs; you will barely be moving the stick. You can probably give it a bit more right cyclic until the left skid just comes off the ground if you want, and then you'll learn how much is too much.
Once you give a bit more collective and the helicopter gets light on the skids, it will probably try scooting to the left. If this is the case, give more right cyclic until the motion stops and you should be just about perfect for a hover. Tony's instructional videos go over scooting the heli on the ground, but you need a training gear for that.