This will all depend on what type of "man boobs" you have.
Holding fatty tissue in that area indicates you have an estrogen dominance/low testosterone problem going on.
This can be caused by many things but, If it is still "soft" and has not hardened over time (true gynocomastia aka bitch tits is only removable in most cases with surgery) then you can reduce your bodyfat levels as well as use an anti-estrogenic compound for a brief time (DIMM is one you can get at GNC or your local supplement shop) along with certain habit changes and implementation of some lifestyle changes such as adding in resistance training (weights) as part of that change. E-GO 2018 P.s. You can't do chest exercises to get rid of "man boobs" ...only overall fat loss will do this. You cannot spot reduce fat. It's hormonal.
Here are a couple of articles I have written on this subject on quora.com. https://www.quora.com/How-can-I-get-rid-of-gynecomastia-caused-by-steroids/answer/Eric-Morrison-18?share=ab29e532&srid=FQlw
Yes, it does! To get rid of man boobs, you're going to want to do a lot of chest exercises, as well as (I know it sucks to hear this) eat right. You're going to want to stick to a routine, and push yourself hard at times. The best exercises for getting rid of man boobs are: 1. Dips (Top priority. Do lots of these to stay in shape. Good for your back, chest and triceps. Do 3 sets of 12 every day with a 30 second break in between every set. Increase the number if you feel you can.) 2. Bench Presses (Don't start light on these, but don't go too heavy. Get a good number of reps in based on your strength. Go with a fairly hard weight and do 3 sets of 8 with 30 second break in between each set.) 3. Pull ups (Not to be confused with chin ups. Pull ups are a great chest exercise, but not everybody can do them. If you can't, you should try to do as many as you can every day. You will see improvement. If you can do them, do 3 sets of 8 daily and spread the 3 out over your day. Don't do them all at once.)
I hope this helps. You should be able to get rid of your man boobs in 2-3 weeks if you keep up with the regimen daily. Alternatively, you could just fast and wait until your body burns your fat, but this is NOT RECOMMENDED. If you ever plan to fast, it's advised to check in with a doctor first to see if it is okay for you to. During fasts, if you're not accustomed to not eating for days on end, there are times where you will feel like you will flat out die, and may even develop Hyponatremia if you drink only distilled water (or acute mineral whatever, I forgot the name of it.) Still, I believe in you, and it's good that you're out here looking out for yourself! Good luck!