I assume your bottle molds are 1/2 faced?

If so, generally you mold each half, let them fully harden.

then, lay a very flat peice of cut metal (I went to a hardware store, and bought a 5x5inch peice of metal - but anything that is flat, even a small pie tin, will do) layed over steaming water.

take one of the halves of the mold, and quickly run it on the now warm-hot metal, to melt the edge of the mold slightly.

Press it to a second mold, hold till the little guy seals up.

With a syringe (I got a perscription from my doctor, oddly enough, to have syringe and needle - but you can get cooking grade needles now), inject into teh hollow, hardened shell, the liqure or flavor you want in the bottles (on teh bottom, for the best and cleanest look).

with a hot/warmed knife, gently tap the bottom of the bottle to seal the hole, or use a bit of melted chocolate to do teh same.

then enjoy !