It doesn't stick too well in my experience, and if you touch it while the Great Stuff is still sticky, Ohhmygod, what a mess you can make of yourself as well as the Great Stuff. About all I've managed to do is to toss a few pebbles into it while it was expanding.
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Patty
Pahsimeroi, Idaho

Dendrobates: auratus blue, auratus Ancon Hill, tinctorius azureus, leucomelas. Phyllobates: vittatus, terribilis, lugubris. Epipedobates: anthonyi tricolor pasaje. Ranitomeya fantastica, imitator, reticulata. Adelphobates castaneoticus, galactonotus. Oophagia pumilio Bastimentos. (updated systematic nomenclature)