This type of ×
(indicatingindicates a close relationship between two things/people) is usually simply ignored, just as we do not bother to read ❤ or ★ aloud in titles and such. "ラビ×ラビ" is read as ラビラビ as if it were one word. "スシロー×寿司ストライカー" would be pronounced with a small pause between スシロー and 寿司ストライカー.
Similar examples from real manga titles:
- HUNTER × HUNTER (pronounced as ハンターハンター)
- サーバント × サービス (pronounced as サーバントサービス)
- ノゾ × キミ (pronounced as ノゾキミ)
When you must read this symbol aloud (e.g., when you need to tell the "spelling" of this title over the phone), you can read this symbolit as かける or バツ.