Is there roll on roll off subs in rugby?

Answer 1

No. The subs are brought on for position replacements which is sometimes tactical as well as using "fresh legs". However, Rugby is one of the few sports that has "Blood Substitutions". these are used when a player is, as the name suggests a bleeding injury. the referee will stop the clock/match and ask for the injured player to be taken off and a replacement (normally for that position) to replace them until the wound can be stitched, stapled and covered to prevent further blood loss.