When you glue a seam either with Tacky glue or Fabric-Tac glue, the trick is to use very little. A syringe is a tool that is used to keep a continuous, very thin line, of glue along the edge of fabric seams. If you don't have a syringe try this: first squeeze out a dot on a hard surface and use a needle tool or toothpick to lightly, and I do mean lightly, touch the glue along the seam line trying to make a continuous thin line of glue. Then allow it to dry until it is opaque. Once the glue gets to that stage, line up the fabric pieces and lightly tap them together. When tap, do not press hard. Once the seam is completely dry, then finger press. Some doll makers take the seam to the ironing board to press the seam. We find that sometimes that makes the seam slightly shiny but you should have no glue marks. Try it. See if it works for you.
Check the Index for more information about glues and using syringes.