You can find lots of videos and pictures of how to swirl the seam online.
Once you have ‘swirled’ use a finger to put the tiniest amount of water where the seams meet - just enough to dampen the fabric slightly - then press as Bobbinalong suggests.
After you have done that putting the block under a heavy book for a few hours or over night can help too.
Last edited by Moira in N.E. England; 07-16-2019 at 12:44 AM.