Prosperist will take your SBD contribution if they are from your author/curation rewards. This means you are sharing your influence and not using any legal tender to fund Prosperist. For now you got another $3.5 SBD reward from your other comment, which makes your total SBD rewards so far will be a total of 6.73 SBD. When there is a payout you can then transfer to Prosperist and become entitled for your Xteem (prosperist) tokens.
More clarity is forthcoming shortly.
Cheers :)