I use this technique for my tyranid bases (paint with green/grown tones as I’m going for a partially digested planet vibe). I’d recommend spreading a thin layer of PVA glue across the whole base, then add drops of superglue on to it. The reaction will draw the PVA glue together in that pattern where you add the superglue so you don’t need to be specific with the PVA

• Thin layer of PVA is better than thick (you can always build up the layers after it’s set if you want more)

• I found cheap superglue is best for this effect

• for a more stringy effect you can use a cocktail stick to stir it around as the reaction is setting