Possible Clues:

• One who sponges on others
• The long fish gets a start up to the sucker
• Scrounger taps general first
• It's a real sucker
• Annelid used in hirudotherapy
• Old doctor about to be taken in by flipping scoundrel
• Shelter companion who would exploit you?
• It drains one after skirt's caught tip of spike
• Runs through Cork church with freeloader
• Parasite sucker