Build over ice in highball, toss into mixing glass and back to combine, top with seltzer, give brief stir.
Varies from Baker's canonical Singapore Sling by using tart cherry shrub instead of cherry cordial and lime, though a lime wedge squeezed and pitched in like Lester would be a nice addition. Named for my 'hood in Boston, and appropriately red.
Swizzled in state of deep thirst à la minute 7/5/11.
Baker's Singapore Sling from this site