This is not a sign of reflux, it is normal baby behaviour to sick up a bit after a feed. It's what muslin squares (AKA sick clothes) are invented for and is the reason you find most mum's of newborn with a muslin over their shoulder at all times.
Always give baby more milk in the bottle than they need.
The aim is that baby doesn't finish the bottle entirely. Any time that happens, or comes close to an empty bottle after a feed, that means you need to start making up bigger bottles from now onwards.
Sounds like your baby is suffering from wind though. Some things that help:
- Always have baby's head higher than their tummy when feeding.
- never let the teat of the bottle be empty, it should always be full of milk at all times during the feed. So watch the angle of the bottle to make sure. Otherwise baby is gulping in air from the bottle.
- keep feeding until baby stops himself, don't take baby off the bottle when actively feeding.
- learn lots of different winding techniques (Google will help). Some work better for different babies.
- keep winding until baby burps.
- it's normal for a bit of milk to come up with the burp. Use a sick cloth / muslin
- after the burp, try winding again for a few mins, there may be more air. If baby brings up milk quite a while after a feed then it's a sign that you didn't wind baby well enough. Try a different technique.
- after a feed / wind / burp / rewind - then reoffer whatever is left in the bottle. Baby may be still hungry after doing the burp. Again, if baby empties the bottle at this point, then start making bigger bottles. Baby should never be emptying the bottle, always offer more than is needed.
- wind again after reoffering the bottle
You'll probably want to put baby down for a sleep after this feed/wind/refeed/rewind cycle. But that's another thread.
Other things to consider is the bottle you are using. You can get anti-wind bottles (Dr Browns) for very windy babies.
Aim to have baby with head above stomach as much as possible when awake.
You could slightly raise the head end of the cot so that the whole cot is angled to keep head higher then stomach.
If baby seems to be guzzing feeds to fast, offer the feed sooner. Have less of a gap between feeds. I favour daytime feeds every 2 hours during the daytime, so that fewer are needed at night.