Ignoring it fully (trying not to think about gay sex, even when masturbating) is sure to fail. I would say especially if you're single, now is EXACTLY the time to figure out a bit more about how your particular bisexuality works. Go really slow if you're new to it, but I think you'll feel once you've had some sexual contact with men, you will enjoy and feel more secure about being open about being bi. Because ultimately, coming out seems hard, but I need to tell you, it is SO much easier that being closeted. You don't need to inform every last distant relative and coworker that you're bi if you generally date women, but being open about it to your family, close friends, and partners can be really great and affirming. I came out as bi about 6 years ago, in my late 20s, and it went very well. I started feeling better about myself, have gotten into much better shape, and am a much more confident and happy person since I came out. I also have had a lot more satisfying sex since, with both hot guys and hot women.
If you're in a monogamous relationship with a woman you care about, which is why you want to "ignore" your gay side, you have a few options.
First, even if you're closeted, you can always enjoy it as a fantasy--everyone in a relationship, whatever their orientation, has fantasies that don't involve their partner. At least allow yourself to enjoy it that way. If you try to repress it, you will just add all this unnecessary guilt and shame that is really corrosive and toxic. At the very least become proud of being bi in your head!
Second, you can come out to your girlfriend and see what she says. In my experience, I have had a couple girls be fine from the start (and even say, "you know, you don't seem 100% straight, so this explains it...") And I had girlfriends react somewhat negatively at first, only to shift over time to be fine with it and even like it. My last girlfriend reacted horribly when I told her, but within a year, was so into it she was constantly mentioning the idea of an MMF threesome. My current girlfriend was a little wary when I first told her, but now says she finds it hot, just like the last one. And she has said if we end up getting married, she would not want me to repress that side of myself, and would rather being monogamish and let me have a hall pass for men, provided I find just one trusted partner at a time and am super safe. (Though honestly, I think I'd rather just have MMF threesomes with her.)
Look, repression is bad for your mental health. You may not want to ever be fully out as bi, which I can understand, especially if you never get emotionally involved with men and your straight side is fairly dominant. But at the very least, don't try to deny this part of you. Over time, that denial will really eat a hole in your psyche. Find someway to be "out," even if just to yourself, that is affirming, that there is nothing wrong or shameful and bad about being a man who love sex with both men and women.
I love being bi, and even if not everyone in the world accepts my sexuality, I at least wish all other bi men felt that way too.